IMAT 2019 Answers & Worked Solution

Full explanation

Given : 60% of income (£21 000) is from the centre stalls. Thus, (60)/(100) × 21,000 = £12,600 for centre stalls. Since centre stalls cost £28 per seat, Number of seats in centre stall = (12,600)/(28) = 450 seats Since every row in the theatre contains 30 seats, Number of centre stall rows = (450)/(30)= 15 rows Thus, the correct option is option B. 15

Full explanation

The argument assumes that fun and education are separate, implying that making a lesson enjoyable does not contribute to learning. This ignores the possibility that students who enjoy their lessons might actually learn better.

Option A : The statement that education is not about happiness may be debatable, but it’s not a flaw in reasoning.

Option B : The flaw in the argument is about how lessons are judged, not about defining education.

Option C : The real flaw is that the argument ignores the link between fun and learning, not just that it exaggerates.

Option D : The argument ignores this possibility, making it a flaw. This is a correct option.

Option E : The flaw is not about patronizing students but about ignoring the benefits of fun in learning.

Full explanation

First, we need to identify the total lawn area to be reseeded.

In dividing the lawn area into 4 parts, (4m × 2m) + (2m × 3m) + (1m × 1m) + (2m × 3m) = 8m² + 6m² + 1m² + 6m² = 21 m² For 21m² lawn area, 50 x 21 g = 1050 g (1.05kg) of seeds are required.

Thus, the least amount of money needs to be spent would be 14 £ (for 1.0 kg) + 2 £ (for 100g) = 16 £ Thus, the correct option is option D. £16.00

Full explanation

The argument claims that wooden floors are more eco-friendly than carpets because carpets are plastic-based and use petrochemical underlay. It then concludes that wooden floors will remain in fashion due to their environmental benefits.

Option A : This might be a reason to prefer wooden floors, but it does not weaken the argument about eco-friendliness.

Option B : The argument already assumes wooden floors have an eco-friendly advantage, so this fact does not contradict it — instead, it strengthens it.

Option C : If most laminate and wood floors also use petrochemicals, then the argument’s main justification for wooden floors being more eco-friendly is weakened. This directly challenges the claim that wooden floors align with “eco-friendly aspirations,” making it the strongest way to weaken the argument. Thus, this is the correct option.

Option D : This challenges the durability of wooden floors, but the argument is not based on durability. The argument claims wooden floors will remain in fashion due to eco-friendliness, not longevity.

Option E : It does not directly weaken the claim that wooden floors are eco-friendly. The argument is about wooden floors’ impact, not the decline of synthetic carpets.

Full explanation

Joker card — this doubled the number of points gained in that event.

Tia

– Scored a total of 14 points.

– 1 event won (6 points) and 3rd on 2 events (1 point each)

– To score 14 points, Tia must have used her joker card on the event she won. (2(6)+1+1=14)

Jessica

– Scored a total of 19 points

– 2 events won (6 points each) and 3rd on 1 event (1 point)

– To score 19 points, Jessica must have used her joker card on one of the events she won. (2(6)+6+1=19)

Carolina

– Scored a total of 14 points

– 1 event won (6 points) and 2nd on 2 events (3 points each) and 3rd on 1 event (1 point)

– To score 14, Carolina must have used her joker card on the event where she was 3rd. (6+3+3+2(1)=14)

Kelly

– Scored a total of 12 points but she did not win any event. So, we can eliminate this option.

Helena

– Scored a total of 13 points.

– 1 event won (6 points) and 3rd on 1 event (1 point)

– To score 13, Helena must have used her joker card on the event she won. (2(6)+1=13)

Thus, 3 girls used joker cards in the event they won. The correct option is C. 3

Full explanation

The passage discusses a study on brain training for people aged 65+. Key findings are mentioned. The study does not claim that training prevents dementia entirely. Instead, it shows that brain training delays its onset. We need to choose the option that is directly supported by the findings mentioned in the argument.

Option A : The passage mentions that brain training improved everyday activities like housework. However, it does not say that older people generally do less housework over time. This statement is not supported by the passage.

Option B : The passage does state that those who had brain training experienced faster decline once diagnosed with dementia, but it never suggests that swift decline is a good or “preferable” thing for anyone — that is simply the study’s finding, not a value judgement, so option B’s claim is not supported by the passage.

Option C : The passage only discusses people who voluntarily participated in brain training. There is no mention that older adults avoid mental challenges unless forced. This is an unsupported generalization.

Option D : This is directly supported: trained individuals developed dementia later than those in the control group. This matches the findings, making it the best conclusion.

Option E : The study showed that brain training benefits lasted for five years, but it does not say that everyone who took part lived that long.

This is an incorrect assumption based on the wording.

Full explanation

The passage discusses whether Near-Death Experiences (NDEs) are purely physiological.

Option A : It is a fact from the passage, not the main conclusion.

The passage uses this fact to support its main claim but does not argue for this specifically.

Option B : It is just a fact supporting the argument, not the conclusion.

Option C : This contradicts the argument! The passage challenges the idea that oxygen deficiency is the sole cause of NDEs. The study suggests that oxygen deficiency alone is not enough to explain NDEs.

Option D : This perfectly matches the passage’s reasoning.

Since cerebral anoxia alone does not explain all NDEs, there must be other, non-physical factors involved. This is the best conclusion that logically follows from the argument.

Option E : The passage actually argues against the idea that NDEs are purely physical. Since not everyone with cerebral anoxia has NDEs, the passage suggests that other factors (not just physical ones) must be involved.

Full explanation

The box has 4 lateral sides and 2 up and down sides.

2 opposite sides will need the same length of string.

For the first pair of lateral sides, 60 cm of string (40 cm for length and 20 cm for height) is needed.

For the second pair of lateral sides, 50 cm of string (30 cm for width and 20 cm for height) is needed.

For each up or down side, 70 cm of string (30 cm for width and 40 cm for length) is required.

Total length of string needed = length of 4 lateral sides + length of up and down sides + length for the knot = 2 (60cm) + 2 (50cm) + 2 (70cm) + 20 cm = 380 cm Thus, the correct option is option D. 3.8 m

Full explanation

If we try to visualize and draw the lines that form the given pattern, the following image emerges. Therefore, the piece that is not needed is the one from option D.

Full explanation

The passage explains that the recent drop in the marlin catch:

– Is not due to environmental conditions

– Is not due to human factors

– Follows a historical pattern of five-year declines alternating with fifteen-year increases, based on six centuries of fishing records.

– Conclusion: The decline is part of a natural long-term cycle.

An assumption is something unstated but necessary for the argument to hold.

For the conclusion (that the marlin catch follows a natural cycle) to be valid, the researchers must have used reliable historical records. If the records were inaccurate, then the entire pattern could be invalid, and the argument would fall apart.

Thus, the assumption is:

E. The records provide accurate information about the catch of marlin off the Madeira coast.

Full explanation

Harper Lee wrote To Kill a Mockingbird, which was published in 1960. The novel is a classic of American literature and deals with themes of racial injustice, moral growth, and empathy. It is set in the American South during the Great Depression and follows Scout Finch, a young girl whose father, Atticus Finch, defends a Black man falsely accused of a crime.

Full explanation

The United Nations (UN) was established in 1945 to promote international cooperation and prevent future conflicts. Its main purposes are outlined in the UN Charter, and they include:

1. To maintain international peace and security

2. To develop friendly relations among nations

3. To achieve international co-operation in solving international problems

4. To be a centre for harmonizing the actions of nations

While the UN supports economic cooperation, it does not focus directly on trade. Trade is mainly handled by other organizations like the World Trade Organization (WTO) and the International Monetary Fund (IMF).

The UN is not responsible for setting trade policies or enforcing trade agreements.

Thus, the purpose that is not stated is option B. To encourage peaceful trade between nations

Full explanation

Madama Butterfly is a famous opera composed by Giacomo Puccini in 1904. It tells the tragic story of Cio-Cio-San (Madama Butterfly), a young Japanese woman who falls in love with an American naval officer, Pinkerton, only to be abandoned and betrayed. The opera is known for its emotional depth and beautiful music, including the famous aria “Un bel dì, vedremo”.

Full explanation

On 1 January 2002, twelve European Union (EU) countries officially adopted Euro coins and banknotes as their currency. These countries were:

Austria, Belgium, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain. Sweden, the United Kingdom, and Denmark chose NOT to adopt the Euro.

Full explanation

Many of Shakespeare’s plays are set in Italy, but A Midsummer Night’s Dream is NOT one of them. Instead, it takes place in Athens, Greece, and the surrounding mystical forest. The play follows the romantic entanglements of four lovers, the antics of the fairy king and queen (Oberon and Titania), and the mischievous Puck.

Full explanation

Placing each event on a timeline:

• The fall of the Western Roman Empire — 476 CE
• The crowning of Charlemagne — 800 CE
• The building of the Taj Mahal — 1632–1653 CE
• The Taiping Rebellion in China — 1850–1864 CE
• The October Revolution in the Russian Empire — 1917

Of these, the October Revolution (1917) is the most recent. Thus, the correct option is option C.

Full explanation

Marie Curie was the first woman to be awarded a Nobel Prize in 1903. She won the Nobel Prize in Physics along with Pierre Curie and Henri Becquerel for their work on radioactivity.

She later became the first person ever to win two Nobel Prizes, receiving the Nobel Prize in Chemistry in 1911 for her discovery of radium and polonium.

Full explanation

The Prisoner’s Dilemma is a famous concept in game theory, a branch of mathematics that studies strategic decision-making.

Full explanation

Hinduism is not attributed to a single founder or a specific revelation to one individual. Instead, it evolved over thousands of years through a combination of religious traditions, cultural practices, and sacred texts like the Vedas and Upanishads. It is considered the world’s oldest major religion and has no single point of origin or founding figure.

Full explanation

The Constitution of the Italian Republic was enacted on 22 December 1947 by the Italian Constituent Assembly (Assemblea Costituente), which was elected in 1946 after the fall of Fascism and the end of World War II.

Full explanation

The Poems of Rumi were not written in China. They were composed by Jalal al-Din Rumi, a Persian poet from the 13th century, in the Persian Empire (modern-day Iran and Afghanistan).

Full explanation

Separation of powers is a fundamental principle in modern democratic states. It ensures that:

– Legislative power (e.g., Parliament, Congress) makes the laws.

– Executive power (e.g., President, Prime Minister, Government) enforces the laws.

– Judicial power (e.g., Courts, Judges) interprets and applies the laws.

This system prevents the concentration of power in one branch and promotes checks and balances.

Thus, the correct answer is option E) Legislative — executive — judicial

Full explanation

Actual size = Image size ÷ Magnification.

Image size = 30 mm = 30,000 µm (since 1 mm = 1,000 µm). Magnification = ×30,000.

Actual size = 30,000 µm ÷ 30,000 = 1 µm.

Bacteria have an average diameter of about 1 µm. Plant cells have a diameter of 10–100 µm. Human cells such as red blood cells, neurons and lymphocytes have a diameter of about 10 µm.

An actual size of 1 µm matches a bacterium, not a plant or human cell. Thus, the correct option is option A, one coccus bacterium.

Full explanation

B lymphocytes are formed and mature in the bone marrow. Then, they are stored and activated in spleen and lymph nodes, where they turn into plasma cells to produce antibodies. Because these antibodies dissolve and act in the blood, this division is called humoral immunity.

For T cells, they are produced in the bone marrow and mature in the thymus. They are the agents of cell-mediated immunity because they coordinate the immune system and directly kill virally infected cells.

Thus, the correct row for B lymphocytes is row 3.

Full explanation

It is mentioned that Familial hypercholesterolemia (FH) is an inherited disease caused by a dominant allele.

For the diseased female and normal male to produce a normal child, the genotype of the diseased female must be heterozygous. (If homozygous dominant, all children must be diseased)

So, in parent generation, mother has heterozygous genotype (F_hF) and father has homozygous recessive genotype (FF). Crossing F_hF and FF will give equal ratio of F_hF and FF.

Thus, in F1 Generation, genotype of diseased male = F_hF (heterozygous)

Genotype of diseased female = F_hF (heterozygous)

Genotype of normal male = FF(homozygous)

The mentioned family tree has 0 homozygous dominant, 3 heterozygous and 2 homozygous recessive. The correct option is option C. row 3.

Full explanation

During anaphase of mitosis, the centromeres split, and sister chromatids are pulled apart. The spindle fibers (microtubules) shorten, pulling chromosomes to opposite poles of the cell. Non-kinetochore microtubules push against each other, lengthening the cell.

Option A: Chromatin condensation occurs mainly in the Prophase.

Option B: Centrioles migrate to opposite poles mainly in the Prophase.

Option C: DNA replication occurs in the S phase of the cell cycle. It is not part of the mitosis process.

Option D: This statement correctly describes the process of anaphase.

Option E: Chromosomes align at the equator of the cell during metaphase.

Thus, the correct option is option D.

Full explanation

In Sympathetic nervous system, preganglionic neurons are short, myelinated and synapse in ganglion that exists just outside the spinal cord. Postganglionic neurons are long, unmyelinated and extend to the target organ. Sympathetic nerves arise from the thoraco-lumbar region of the spinal cord.

In the Parasympathetic nervous system, preganglionic neurons are long, myelinated and synapse in ganglion that exists close to the target organ. Postganglionic neurons are short and unmyelinated. Parasympathetic nerves arise from the brainstem and sacral part of the spinal cord.

Option A : There is no ganglion, So, this is not a possible pathway for a parasympathetic Nervous system. Since the nerve pathway passes through the dorsal root, connecting between brain and target organ, it should be a cranial nerve (sensory).

Option B : Ganglion is present but it is closed to the spinal cord. Thus, this is not a correct option. This image represents the sensory pathway for the sympathetic nervous system.

Option C : Ganglion is present and it is closed to the target organ. Thus, this is a possible route for impulses passing along a parasympathetic neuron.

Option D : No ganglion is present. Thus, this is not a possible pathway for a parasympathetic Nervous system. This could be the motor pathway of a spinal nerve.

Option E : No ganglion is present. Thus, this is not a possible pathway for a parasympathetic Nervous system. This could be the sensory pathway of a spinal nerve.

Full explanation

Viruses derive their envelope from the host’s cell membrane. Thus, it is composed of a double layer of phospholipids. (Phosphate + 2 fatty acid chains + glycerol)

Viral capsids are mainly composed of several types of proteins (polymers of amino acids)

Genetic material can be DNA or RNA, single-stranded or double-stranded. (nucleotides joined together by phosphodiester bonds)

Thus, the row that shows the correct component of the 3 structures is row 4.

Full explanation

Organisms contain the same set of genes in every cell in the body, and the difference in gene expression is due to the regulatory factors that turn on or off specific genes. Thus, among the three statements that the student wrote, only the first statement is correct.

The 2nd statement is wrong because genes are the same and alleles are the same in both white hair follicle cells and black hair follicle cells.

The third statement is wrong for the same reason: white hair follicle cells do not contain any alleles that are different from — or more recessive than — those in any other cell of the body.

Thus, the correct option is option D. 1 only.

Full explanation

Tissue is a group of similar cells that work together to perform a specific function. There are 4 main types of tissues : Epithelial, connective, nervous and muscle tissues.

An organ is a structure made up of different types of tissues working together to perform a specific function.

Among the 3 given structures, cartilage (connective) and endothelium are tissues, and skin is an organ that is composed of blood vessels (contains all types of tissue), epithelium, and nerves.

Full explanation

P ATT CCG GGA TTC CCT Q ATT CCG GAT TGC ACT Addition: A mutation where one or more nucleotides are added to the DNA sequence.

Deletion: A mutation where one or more nucleotides are removed from the DNA sequence.

Substitution: A mutation where one nucleotide is replaced by another.

Comparing the two given nucleotide sequences, differences appear starting from the 3rd triplet.

In P, if Guanine is deleted in the third triplet (deletion) and G is added between T and C in the fourth triplet (addition), and first C is replaced by A in the last triplet (substitution), it will result in the Q sequence.

Thus, all three types of mutations — addition, deletion, and substitution — can explain the differences between P and Q.

Full explanation

An experiment is done to observe the effect of various chemicals (dilute HCl, ethanol, and water at 20 °C) on the permeability of the cell surface membranes.

Ethanol is a nonpolar solvent that can dissolve the lipid bilayer and increase membrane permeability.

HCl is an acid, and even when diluted, it can denature membrane proteins by disrupting hydrogen bonds and ionic interactions.

Water at 20 °C will not disrupt the cell membrane.

Thus, the correct row is row 3 (Option E)

Full explanation

An amino acid has an alpha carbon attached to an amino group, a carboxyl group, a hydrogen, and a side chain ‘R’.

Fatty acid has a carboxyl group and a long chain hydrocarbon.

Glucose is a 6-carbon carbohydrate monomer. It contains 5 hydroxyl groups and an aldehyde group (-CHO).

Glycerol is a 3-carbon molecule that contains 3 hydroxyl groups, so it is a triol alcohol.

Thus, rows 1, 2, and 4 are correct.

Full explanation

During muscle contraction, the sarcomere shortens as the Z-lines (Z-discs) move closer together. The I-band (region with only thin filaments) shortens, and the H-zone (region with only thick filaments) narrows or disappears. The A-band (length of thick filaments) remains unchanged because the thick filaments do not change length. The M-line (center of the sarcomere, where thick filaments are anchored) remains in place, but overall, the sarcomere shrinks in length. Thin filaments (actin) slide over thick filaments (myosin) without either filament changing in size, causing the entire muscle to contract through the sliding filament mechanism.

Full explanation

Label 1 — Bowman’s capsule: This is the site of ultrafiltration where blood plasma, including urea, is filtered by the glomerulus into the nephron. Large molecules like proteins are retained, but urea freely passes into the filtrate.

Label 2 — Descending limb of the loop of Henle: Water is reabsorbed by osmosis due to the surrounding high osmolarity of the medulla. However, solutes like urea are not reabsorbed here, so urea concentration in the filtrate increases as water leaves.

Label 3 — Distal convoluted tubule: This segment reabsorbs water and salts under hormonal regulation (like aldosterone), but it does not significantly reabsorb urea. Urea remains concentrated in the filtrate as volume decreases.

Label 4 — Collecting duct: Water reabsorption continues here, largely under the influence of antidiuretic hormone (ADH). Although water is removed, urea remains and diffuses out in the lower parts of the duct to help maintain the osmotic gradient in the medulla.

Full explanation

In plants, cells in the leaves contain both mitochondria (for cellular respiration) and chloroplasts (for photosynthesis). CO2 is produced by the mitochondria at any time of the day, and it can be used back by the plant for photosynthesis. Thus, all 3 mentioned statements are correct.

Full explanation

Option A: Incorrect. Ligase enzymes act as molecular glues by joining two DNA fragments through the formation of phosphodiester bonds between the sugar-phosphate backbones. They do not form hydrogen bonds, which are instead responsible for the base pairing between complementary nucleotides.

Option B: Incorrect. Restriction enzymes act as molecular scissors. They recognize specific DNA sequences (restriction sites) and cut the DNA at or near those sites, breaking phosphodiester bonds, not hydrogen bonds.

Option C: This is a correct statement. A restriction enzyme cuts DNA by breaking the phosphodiester bonds in the sugar-phosphate backbone at specific recognition sites.

Option D: Incorrect. Ligase enzymes form phosphodiester bonds between DNA fragments; they do not break them.

Option E: Incorrect. Restriction enzymes break phosphodiester bonds in the DNA backbone at specific recognition sites.

Full explanation

In mitosis, a single cell replicates its DNA and then divides once, producing two genetically identical daughter cells from each parent cell. Because every cell present at the start of a round divides into two, the total number of cells doubles with each complete round of mitosis, not increases by a fixed amount.

Starting from 1 cell: after round 1 there are 2 cells, after round 2 each of those 2 cells has divided so there are 4, after round 3 there are 8, and so on. Doubling repeatedly like this is exponential growth, and after n rounds of division the cell count is 2ⁿ (each round multiplies the previous total by 2, so the factor of 2 is applied n times).

Here the cell divides by mitosis ten times, so n = 10: 2¹⁰ = 1024 cells.

Option A (64) and Option D (100) both come from arithmetic that ignores the doubling pattern (for example treating the growth as linear or as 10×10 rather than 2¹⁰). Options B (11) and C (10) come from counting the ten divisions themselves, or the ten divisions plus the original cell, instead of the population that those divisions actually produce.

Thus, the correct option is option E.

Full explanation

Option A: Incorrect. Increasing oxygen partial pressure increases hemoglobin’s affinity for oxygen, making it less likely to release oxygen, not more. Oxygen partial pressure (pO₂) affects hemoglobin’s affinity for oxygen. At high pO₂ (lungs), hemoglobin binds oxygen tightly; at low pO₂ (tissues), its affinity decreases, promoting oxygen release. This relationship is key for efficient oxygen transport.

Option B: Incorrect. In aerobic respiration, glucose is broken down in the presence of oxygen to produce carbon dioxide (CO₂), water, and ATP. The CO₂ released dissolves in blood and reacts with water to form carbonic acid, which quickly dissociates into hydrogen carbonate ions (HCO₃⁻) — an important way CO₂ is transported in the blood. Lactic acid is not produced in significant amounts during aerobic respiration; it mainly forms during anaerobic respiration when oxygen is lacking, such as during intense exercise. Thus, aerobic respiration leads to hydrogen carbonate ion formation but not to lactic acid accumulation.

Option C: This is a correct statement. The Bohr effect describes how high carbon dioxide levels and low pH in active tissues lower hemoglobin’s affinity for oxygen, helping release oxygen where it’s needed most.

Option D: Incorrect. While some CO2 is transported as carbaminohemoglobin, the majority is transported as bicarbonate ions (not carbaminohemoglobin)

Option E: Myoglobin has a higher affinity for oxygen than hemoglobin, meaning it is more saturated at lower oxygen partial pressures. Myoglobin is a small, oxygen-binding protein found mainly in muscle tissue. It stores and releases oxygen to muscle cells, especially during periods of high metabolic demand. Structurally, myoglobin consists of a single polypeptide chain and a heme group that binds oxygen. Unlike hemoglobin, which transports oxygen in the blood and has four subunits, myoglobin has only one subunit and binds oxygen more tightly. It is crucial for maintaining oxygen supply during intense muscular activity and provides muscles with a readily available oxygen reserve.

Full explanation

Process 1 – Muscle contraction: Involves calcium ions (Ca²⁺), which trigger the interaction between actin and myosin filaments, leading to contraction.

Process 2 – Nerve impulse transmission across a synapse: Relies on sodium (Na⁺) and potassium (K⁺) ions to generate action potentials, and calcium ions (Ca²⁺) to stimulate neurotransmitter release at synaptic terminals.

Process 3 – Photosynthesis: Uses hydrogen ions (H⁺) to create a proton gradient across the thylakoid membrane, driving ATP synthesis during the light-dependent reactions.

Process 4 – Oxidative phosphorylation: Involves the movement of hydrogen ions (H⁺) across the inner mitochondrial membrane to form a proton gradient, essential for ATP production.

Thus, the processes that involve ions are 1, 2, 3 and 4.

Full explanation

When sugar is added to ice, the sugar molecules interfere with the orderly arrangement of water molecules in the ice lattice. This disruption lowers the melting point (also called freezing point depression). As a result, the mixture now melts at a lower temperature than pure ice.

– Statement 1 is incorrect: Sugar does not directly give energy to the water molecules.

– Statement 2 is incorrect: the melting point becomes lower, not higher.

– Statement 3 is correct: the melting point is lowered, explaining why the ice melted even though the temperature remained at -1 °C.

Full explanation

To identify a redox reaction, we need to check the oxidation number changes between reactants and products in a reaction.

1. 4LiH + AlCl₃ → 3LiCl + LiAlH₄ LiH : Li (+1), H (-1)

AlCl₃: Al (+3), Cl (-1)

LiCl : Li (+1), Cl (-1)

LiAlH₄: Li (+1), Al (+3), H (-1)

The oxidation number of each species does not change. This is not a redox reaction.

2. N₂O₃ + 3H₂O → 2H₃O+ + 2NO₂– N₂O₃: N (+3), O (-2)

H₂O: H (+1), O (-2)

H₃O+: H (+1), O (-2)

NO₂– : N ((+3), O (-2)

The oxidation number of each species does not change. This is not a redox reaction.

3. NH₄NO₃ → 2H₂O + N₂O N in NH₄⁺ = -3, N in NO₃⁻ = +5 H₂O: H is +1, O is -2 N in N₂O = +1 Nitrogen in NH₄⁺ (-3) is oxidized to N₂O (+1). Nitrogen in NO₃⁻ (+5) is reduced to N₂O (+1). This is a redox reaction.

Full explanation

We are given the reversible reaction A + 2B ⇌ 2C + D, with the equilibrium amounts (in moles) all measured in the same vessel of volume V.

Concentration is just moles ÷ volume, so: [A] = 0.5/V, [B] = 0.2/V, [C] = 0.5/V, [D] = 0.8/V.

The equilibrium constant expression, products over reactants (each raised to its coefficient in the equation), is:

Kc = ([C]²[D]) / ([A][B]²)

Numerator: [C]²[D] = (0.5/V)² × (0.8/V) = 0.2/V³.

Denominator: [A][B]² = (0.5/V) × (0.2/V)² = 0.02/V³.

The V³ terms cancel out (which is why the volume V was never actually given a value): Kc = (0.2/V³) ÷ (0.02/V³) = 0.2/0.02 = 10.

Thus, the correct option is option C, 10.

Full explanation

8 g of a compound contains 3 g of C and 1 g of H.

Mass of O = 8 – (3+1) = 4g First, we must convert the mass into mole.

Mole of C contained = (mass)/(molar mass) = (3g)/(12g/mol) = 0.25mol Mole of H contained = (1g)/(1g/mol) = 1 mol Mole of O contained = (4g)/(16g/mol) = 0.25 mol Then, find the whole number ratio of the moles of the elements.

C: H: O 0.25: 1: 0.25 1: 4: 1 Thus, the empirical formula of this compound would be CH₄O.

The molecular formula must be a multiple of the empirical formula CH₄O. Looking at the answer choices, only option E. CH₄O matches the whole number ratio of the elements. Thus, CH₄O is the correct answer.

Full explanation

The boiling point is primarily influenced by intermolecular forces, not the strength of covalent bonds within molecules. The key forces at play here are: Dispersion forces and Dipole-Dipole Forces.

Option A: Boiling point depends on intermolecular forces, not ionic size, in this case. The boiling point of a substance is directly related to the strength of its intermolecular forces. Stronger intermolecular forces (like hydrogen bonds or ionic interactions) require more energy to overcome, resulting in a higher boiling point. Conversely, weaker forces (like London dispersion forces) mean less energy is needed, leading to a lower boiling point.

Option B: Covalent bonds do not have a primary effect on the strength of intermolecular forces.

Option C: Hydrogen bonding occurs only in H-N, H-O, and H-F. Hydrogen bonding occurs when hydrogen is covalently attached to a highly electronegative atom like N, O, or F (hydrogen donor), and this hydrogen is attracted to a lone pair on another electronegative atom (hydrogen acceptor) in a nearby molecule. This creates a strong intermolecular force.

Option D: In fact, HBr is more polar than HI, leading to a stronger dipole-dipole force between molecules, but it is not the deciding factor.

Since iodine (I) is larger than bromine (Br), the HI molecule has more electrons and a more polarizable electron cloud, leading to stronger dispersion forces. This makes HI’s boiling point higher than HBr’s. Thus, the correct option is option E.

Full explanation

Element Z reacts with water at room temperature to release hydrogen gas, indicating it is a metal. The oxide of Z is a solid at room temperature, does not conduct electricity in solid form (only when molten), and reacts with acids — these are typical properties of a basic oxide.

– Group VII elements are non-metals and do not form basic oxides, so they are excluded.

– Transition metals and Group III elements often form oxides with variable oxidation states and more complex formulas, not simple ZO-type oxides.

– Group I metals form oxides with the formula M₂O, corresponding to a +1 oxidation state, not +2.

The formula ZO suggests that Z forms a +2 ion, which is characteristic of Group II metals (alkaline earth metals). Additionally, Group II metals, like calcium and magnesium, react with water (though some more slowly) and form basic oxides with the general formula MO.

Thus, element Z belongs to Group II.

Full explanation

A positive ion (cation) is formed when an atom loses electrons. Since protons are positively charged and electrons are negatively charged, having more protons than electrons results in an overall positive charge. The number of neutrons does not affect the ion’s charge because neutrons are neutral.

Full explanation

CO₂: Shape – linear geometry (symmetrical shape) and net dipole moment is zero.

H₂O: Shape – Bent shape (not symmetrical), Net dipole moment present.

NH₃: Shape – trigonal pyramidal shape (not symmetrical), net dipole moment present.

Thus, H₂O and NH₃ have overall permanent dipole moments.

Full explanation

HCl is added to NaOH solution drop by drop, and the NaOH solution neutralizes little by little, which can be observed by the color changes. (violet to blue)

After 50 ml of HCl is completely added to 50 ml of NaOH, the solution is completely neutralized, and the solution turns green.

Thus, as HCl is added, the solution color will change through the following steps. violet → blue → green.

Full explanation

Tritium has a relative atomic mass of 3.

Protium has a relative atomic mass of 1.

Relative atomic mass of a sample that contains 50% tritium and 50% protium = (3 × 0.5) + (1 × 0.5) = 1.5 + 0.5 = 2

Full explanation

1. CH₃CH₂OH and CH₃OCH₃ They have the same molecular formula (C₂H₆O) with different connectivity of atoms. The first structure is an ethanol, and the second structure is a dimethyl ether. This pair represents structural isomers.

2. CH₃CH(CH₃)CH₂CH₂CH₃ and CH₃CH₂CH₂CH(CH₃)CH₃ :

They have the same molecular formula (C₆H₁₄) with the same connectivity CH₃ group is connected to the second C of the molecule. This pair does not represent structural isomers.

3. CH(OH)=CHCH₂OH and CH₃CH₂COOH They have the same molecular formula (C₃H₆O₂) with different connectivity of atoms. First structure is an ester and the second structure is a carboxylic acid. This pair represents structural isomers.

Thus, structural isomer pairs are 1 and 3.

Full explanation

The question wants to make 500 mL of a solution of concentration 3.0 mol / L. What mass is required?

Convert 500 ml (0.5 L) to moles.

Number of moles = 3 mol/L × 0.5 L = 1.5 mole Then, convert the mole into mass.

Molar mass of SO₂ = S + 2(O) = 32 + 2 (16) = 64 g/mol Mass of sulfur dioxide = mole x molar mass = 1.5 mol x 64 g/mol = 96 g

Thus, the correct option is option E, 96 g.

Full explanation

The car starts from rest, so u = 0, and accelerates for 5.0 s at a = 4.0 m/s². Using v = u + at: v_max = 0 + (4.0 m/s² × 5.0 s) = 20 m/s.

After that, the car continues at this constant speed of 20 m/s for the final 20 seconds. Distance d = v_max × t = 20 m/s × 20 s = 400 m.

Hence, the correct answer is (B).

Full explanation

The mean mass of the three babies is 2.1 kg, so their total mass = 3 × 2.1 = 6.3 kg.

Let the masses be m₁ ≤ m₂ ≤ m₃. The lightest baby’s mass is given: m₁ = 1.8 kg. The range = m₃ − m₁ = 0.7 kg, so m₃ = 1.8 + 0.7 = 2.5 kg.

Since the total mass and the masses of the lightest and heaviest babies are now known, the mass of the middle (median) baby is: m₂ = 6.3 − (m₁ + m₃) = 6.3 − (1.8 + 2.5) = 6.3 − 4.3 = 2.0 kg.

Hence, the correct answer is (D).

Full explanation

The upthrust equals the weight of the liquid displaced by the stone. The volume of liquid displaced equals the volume of the stone (fully submerged) = 200 cm³, and the liquid’s density = 1.20 g/cm³.

Mass of displaced liquid = volume × density = 200 cm³ × 1.20 g/cm³ = 240 g = 0.24 kg.

Upthrust = weight of displaced liquid = mass × g = 0.24 kg × 10.0 N/kg = 2.40 N.

Hence, the correct answer is (E).

Full explanation

For an ideal gas at constant temperature (an isothermal process), pressure and volume are related by Boyle’s Law: P ∝ 1/V, or PV = constant.

When P is plotted against V, the graph is a hyperbola — a curved line with a negative gradient. As V decreases, the magnitude of the gradient (steepness) of the curve decreases.

Hence, the correct answer is (B).

Full explanation

Prime factorise each number: 360 = 2³ × 3² × 5; 500 = 2² × 5³; 700 = 2² × 5² × 7.

The highest common factor takes the lowest power of each prime factor common to all three numbers: 2² (the lowest power of 2 present, from 500 and 700) and 5¹ (the lowest power of 5 present, from all three).

So, HCF = 2² × 5.

Hence, the correct answer is (D).

Full explanation

Combine the fractions over a common denominator: 3/x + 2/(x − 2) = 1 ⇒ [3(x − 2) + 2x] / [x(x − 2)] = 1.

Multiplying out: 3x − 6 + 2x = x² − 2x ⇒ 5x − 6 = x² − 2x ⇒ x² − 7x + 6 = 0.

Factorising: x² − x − 6x + 6 = 0 ⇒ (x − 1)(x − 6) = 0, so x = 1 or x = 6.

Sum of solutions = 1 + 6 = 7. (Alternatively, by Vieta’s formula for ax² + bx + c = 0, sum of roots = −b/a = −(−7)/1 = 7.)

Hence, the correct answer is (E).

Full explanation

Express all terms as powers of 2: 8 = 2³, so 8²ⁿ = (2³)²ⁿ = 2⁶ⁿ. Also 4 = 2², so 4ⁿ = (2²)ⁿ = 2²ⁿ.

The expression becomes (2⁶ⁿ × 2²ⁿ)/2ⁿ = 2^6n+2n−n = 2⁷ⁿ.

Hence, the correct answer is (C).

Full explanation

By Coulomb’s Law, F = kq₁q₂/r². Initially, F = k(1.5 × 10⁻⁷)² / (0.10)².

After the change, F′ = k(4.5 × 10⁻⁷)(6 × 10⁻⁷) / (0.20)².

Taking the ratio: F′/F = [(4.5 × 6)/(1.5)²] × [(0.1)²/(0.2)²] = (27/2.25) × (1/4) = 12 × 1/4 = 3.

So F′ = 3F.

Hence, the correct answer is (E).