Question 1
What happens to the volume of a fixed mass of gas when pressure and temperature are separately increased?

▶️ Answer/Explanation
✅ Answer: (C)
Question 2
Which gas diffuses most quickly at room temperature and pressure?
A. \( \mathrm{CH_4} \)
B. \( \mathrm{C_2H_6} \)
C. \( \mathrm{CO} \)
D. \( \mathrm{SO_2} \)
▶️ Answer/Explanation
✅ Answer: (A)
Question 3
Which statement defines nucleon number?
A. It is the total number of protons in the nucleus of an atom.
B. It is the total number of electrons surrounding the nucleus of an atom.
C. It is the total number of neutrons in the nucleus of an atom.
D. It is the total number of protons and neutrons in the nucleus of an atom.
▶️ Answer/Explanation
✅ Answer: (D)
Question 4
The symbols of four atoms are listed.
\( ^{24}_{12}\mathrm{Mg} \quad ^{27}_{13}\mathrm{Al} \quad ^{31}_{15}\mathrm{P} \quad ^{40}_{18}\mathrm{Ar} \)
Which atoms have more neutrons than protons?
A. 1 and 2
B. 2 and 3
C. 2 and 4
D. 3 and 4
▶️ Answer/Explanation
Atom 1 \(^{24}_{12}\mathrm{Mg}\): neutrons = 24 − 12 = 12 (equal to protons).
Atom 2 \(^{27}_{13}\mathrm{Al}\): neutrons = 27 − 13 = 14 (more than protons).
Atom 3 \(^{31}_{15}\mathrm{P}\): neutrons = 31 − 15 = 16 (more than protons).
Atom 4 \(^{40}_{18}\mathrm{Ar}\): neutrons = 40 − 18 = 22 (more than protons).
The atoms with more neutrons than protons are 2, 3, and 4. Looking at the given options, 2 and 4 is the correct pair.
✅ Answer: (C)
Question 5
Which statement describes all positive ions?
A. Positive ions have more electrons than neutrons.
B. Positive ions have more protons than neutrons.
C. Positive ions have more electrons than protons.
D. Positive ions have more protons than electrons.
▶️ Answer/Explanation
✅ Answer: (D)
Question 6
A sample of copper has a relative atomic mass of 63.5.
What are the relative abundances of the isotopes in this sample of copper?
A. \(25\%\) \(^{63}\mathrm{Cu}\) and \(75\%\) \(^{65}\mathrm{Cu}\)
B. \(50\%\) \(^{63}\mathrm{Cu}\) and \(50\%\) \(^{65}\mathrm{Cu}\)
C. \(75\%\) \(^{63}\mathrm{Cu}\) and \(25\%\) \(^{65}\mathrm{Cu}\)
D. \(90\%\) \(^{63}\mathrm{Cu}\) and \(10\%\) \(^{65}\mathrm{Cu}\)
▶️ Answer/Explanation
Using the formula for relative atomic mass: \(63x + 65(1-x) = 63.5\)
\(63x + 65 – 65x = 63.5\)
\(-2x = -1.5\)
\(x = 0.75 = 75\%\)
Therefore, \(75\%\) \(^{63}\mathrm{Cu}\) and \(25\%\) \(^{65}\mathrm{Cu}\).
✅ Answer: (C)
Question 7
Which diagram shows the outer shell electron arrangement for a molecule of methanol, \(\mathrm{CH_3OH}\)?

▶️ Answer/Explanation
✅ Answer: (A)
Question 8
Rescuers are drilling through fallen rock in order to rescue some people trapped in a cave. The drill needs lubricating from time to time.
Four statements are made about the materials used for the drill tip and the lubricant to explain the reasons for their use.
- Diamond is used for the drill tip as it does not conduct electricity.
- Diamond is used for the drill tip as it is very hard.
- Graphite is used as the lubricant as it conducts electricity.
- Graphite is used as the lubricant as it is soft and slippery.
Which statements are correct?
A. 1 and 3
B. 1 and 4
C. 2 and 3
D. 2 and 4
▶️ Answer/Explanation
✅ Answer: (D)
Question 9
Which compound has an empirical formula that is the same as its molecular formula?
A. butane
B. but-1-ene
C. butanoic acid
D. butan-1-ol
▶️ Answer/Explanation
Butane: molecular formula \(\mathrm{C_4H_{10}}\), empirical formula \(\mathrm{C_2H_5}\) (different).
But-1-ene: molecular formula \(\mathrm{C_4H_8}\), empirical formula \(\mathrm{CH_2}\) (different).
Butanoic acid: molecular formula \(\mathrm{C_4H_8O_2}\), empirical formula \(\mathrm{C_2H_4O}\) (different).
Butan-1-ol: molecular formula \(\mathrm{C_4H_{10}O}\), empirical formula \(\mathrm{C_4H_{10}O}\) (same).
✅ Answer: (D)
Question 10
Which row identifies the charge on the chromium ion and on the sulfate ion in \(\mathrm{Cr_2(SO_4)_3}\)?

▶️ Answer/Explanation
✅ Answer: (C)
Question 11
Which statement describes a saturated solution?
A. It is a solution that contains the maximum concentration of solute.
B. It is a solution that contains the maximum amount of solvent.
C. It is a hydrocarbon that contains both double and single bonds.
D. It is a hydrocarbon that contains only single bonds.
▶️ Answer/Explanation
✅ Answer: (A)
Question 12
Calcium carbonate decomposes when heated strongly.
\(\mathrm{CaCO_3(s) \rightarrow CaO(s) + CO_2(g)}\)
How many gaseous molecules are produced when \(10.0\,\text{g}\) of calcium carbonate is completely decomposed?
A. \(1.00 \times 10^{22}\)
B. \(1.20 \times 10^{23}\)
C. \(6.02 \times 10^{22}\)
D. \(6.02 \times 10^{23}\)
▶️ Answer/Explanation
Moles of \(\mathrm{CaCO_3} = \frac{10.0}{100} = 0.10\,\text{mol}\).
From the equation, 1 mole of \(\mathrm{CaCO_3}\) produces 1 mole of \(\mathrm{CO_2}\) molecules.
Number of \(\mathrm{CO_2}\) molecules = \(0.10 \times 6.02 \times 10^{23} = 6.02 \times 10^{22}\).
✅ Answer: (C)
Question 13
Which product is initially obtained at each electrode during the electrolysis of concentrated aqueous sodium chloride?

▶️ Answer/Explanation
At the cathode (−): \(\mathrm{H^+}\) ions are discharged in preference to \(\mathrm{Na^+}\) ions because \(\mathrm{H^+}\) is more easily reduced. Hydrogen gas (\(\mathrm{H_2}\)) is produced.
At the anode (+): \(\mathrm{Cl^-}\) ions are discharged in preference to \(\mathrm{OH^-}\) ions due to the high concentration of chloride ions. Chlorine gas (\(\mathrm{Cl_2}\)) is produced.
✅ Answer: (A)
Question 14
Molten lead(II) bromide is electrolysed using inert electrodes.

Which statement describes the movement of electrons?
A. from X to Y through the external wire
B. from Y to X through the external wire
C. from X to Y through the electrolyte
D. from Y to X through the electrolyte
▶️ Answer/Explanation
✅ Answer: (A)
Question 15
In a fuel cell, a fuel is oxidised to produce electricity. Which row describes the fuel and the oxidising agent used?

▶️ Answer/Explanation
✅ Answer: (B)
Question 16
Which statement about reactions is correct?
A. A reaction that is vigorous at room temperature has a high activation energy.
B. If \(\Delta H\) for a reaction is positive, bond making in the formation of the products is endothermic.
C. In an exothermic reaction, the energy required to break bonds is less than the energy released to make bonds.
D. Reactions with a positive enthalpy change always transfer thermal energy to the surroundings.
▶️ Answer/Explanation
(A) is false — vigorous reactions at room temperature have low activation energy.
(B) is false — bond making is always exothermic, regardless of \(\Delta H\) sign.
(D) is false — positive \(\Delta H\) means endothermic; energy is absorbed from the surroundings.
✅ Answer: (C)
Question 17
Ethene reacts with hydrogen to form ethane.

The bond energies are shown in the table.

What is the enthalpy change for the reaction?
A. −290 kJ/mol
B. −120 kJ/mol
C. +120 kJ/mol
D. +290 kJ/mol
▶️ Answer/Explanation
Bonds broken: C=C (614) + H−H (436) = 1050 kJ
Bonds formed: C−C (350) + 2 × C−H (2 × 410 = 820) = 1170 kJ
\(\Delta H = +1050 – 1170 = -120\,\text{kJ/mol}\)
The negative value indicates an exothermic reaction.
✅ Answer: (B)
Question 18
Zinc reacts with dilute hydrochloric acid.
Which statement about the particles in the reaction is correct?
A. Increasing the concentration of dilute hydrochloric acid increases the collision rate but has no effect on the activation energy.
B. Increasing the concentration of dilute hydrochloric acid increases the collision rate and the activation energy.
C. Increasing the temperature of the reaction increases the activation energy.
D. Increasing the temperature of the reaction causes all collisions to lead to a reaction.
▶️ Answer/Explanation
✅ Answer: (A)
Question 19
Ethanol is manufactured by the addition of steam to ethene.
\(\mathrm{C_2H_4(g) + H_2O(g) \rightleftharpoons C_2H_5OH(g)}\)
The reaction conditions are \(300^{\circ}\mathrm{C}\) and 60 atm.
The forward reaction is exothermic.
Which rows describe the effect on the equilibrium yield of \(\mathrm{C_2H_5OH}\) when the stated change is made?

A. 1 and 2
B. 1 and 3
C. 2 only
D. 3 only
▶️ Answer/Explanation
Statement 2: The forward reaction is exothermic. Decreasing temperature favours the exothermic reaction, shifting equilibrium to the right, increasing yield — correct.
Statement 3: 2 moles of gaseous reactants → 1 mole of gaseous product. Decreasing pressure favours the side with more gas moles (reactants), shifting equilibrium left, decreasing yield — incorrect.
✅ Answer: (A)
Question 20
Which row identifies the conditions used to make sulfur trioxide in the Contact process?

▶️ Answer/Explanation
✅ Answer: (B)
Question 21
Which statement describes a base?
A. It reacts with ammonium chloride to produce ammonia gas.
B. It reacts with calcium carbonate to produce carbon dioxide gas.
C. It reacts with copper to produce hydrogen gas.
D. It turns blue litmus red.
▶️ Answer/Explanation
(B) describes an acid reacting with a carbonate.
(C) is incorrect — copper does not react with bases to produce hydrogen.
(D) describes an acid — acids turn blue litmus red; bases turn red litmus blue.
✅ Answer: (A)
Question 22
The equation shows the reaction between copper and concentrated nitric acid.
\(\mathrm{Cu(s) + 4HNO_3(aq) \rightarrow Cu(NO_3)_2(aq) + 2NO_2(g) + 2H_2O(l)}\)
Which element is reduced in this reaction?
A. oxygen
B. nitrogen
C. copper
D. hydrogen
▶️ Answer/Explanation
✅ Answer: (B)
Question 23
The Periodic Table shows the position of four different elements.

Which row is correct?

▶️ Answer/Explanation
✅ Answer: (C)
Question 24
Dilute acid R and dilute acid S have the same concentration.
The same volume of each dilute acid is reacted separately with the same mass of magnesium ribbon. Both reactions are carried out at room temperature and pressure.
The volume of hydrogen produced is measured.
A graph of the results shows.

Which statement about the reactions is correct?
A. Acid S reacts faster than acid R.
B. The final volume of hydrogen produced in each reaction is different.
C. Acid R is a stronger acid than acid S.
D. Acid S is a stronger acid than acid R.
▶️ Answer/Explanation
✅ Answer: (C)
Question 25
Which metal oxide reacts with aqueous sodium hydroxide to form a salt and water?
A. calcium oxide
B. copper(II) oxide
C. sodium oxide
D. aluminium oxide
▶️ Answer/Explanation
✅ Answer: (D)
Question 26
Which row identifies a transition element?

▶️ Answer/Explanation
✅ Answer: (A)
Question 27
Which statement about Group I or Group VII elements is correct?
A. Group VII elements are monatomic non-metals.
B. Lithium is more reactive with water than caesium.
C. The melting point of Group I metals increases down the group.
D. Potassium bromide reacts with chlorine to produce an orange solution.
▶️ Answer/Explanation
(A) is false — Group VII halogens are diatomic (\(\mathrm{F_2, Cl_2, Br_2, I_2}\)).
(B) is false — reactivity increases down Group I, so caesium is more reactive than lithium.
(C) is false — melting points decrease down Group I.
✅ Answer: (D)
Question 28
Some information about four metals P, Q, R and S is listed.
Metal P does not react with dilute hydrochloric acid.
Metal Q is more reactive than magnesium.
Metal R reacts rapidly with cold water to produce hydrogen.
Metal S reacts with dilute hydrochloric acid to produce hydrogen.
Which row identifies P, Q, R and S?

▶️ Answer/Explanation
Q is more reactive than Mg → Q must be K, Na, or Ca.
R reacts rapidly with cold water → R must be K, Na, or Ca.
S reacts with dilute HCl to produce H₂ → S must be above hydrogen but not necessarily above Mg (Mg, Al, Zn, Fe).
In option (B): P = Cu (below H, correct), Q = K (more reactive than Mg, correct), R = Ca (reacts with cold water, correct), S = Mg (reacts with dilute HCl producing H₂, correct).
✅ Answer: (B)
Question 29
Cars are fitted with catalytic converters.
Which equation represents a reaction that takes place in a catalytic converter?
A. \(\mathrm{CO_2 + NO_2 \rightarrow CO + NO + O_2}\)
B. \(\mathrm{2CO + 2NO \rightarrow 2CO_2 + N_2}\)
C. \(\mathrm{CO_2 + N_2 \rightarrow C + 2NO}\)
D. \(\mathrm{C + NO_2 \rightarrow CO + NO}\)
▶️ Answer/Explanation
✅ Answer: (B)
Question 30
Three statements about greenhouse gases and global warming are listed.
- A greenhouse gas molecule can absorb and emit thermal energy.
- The Earth is a source of thermal energy.
- Thermal energy emitted by a greenhouse gas molecule is sent out in all directions.
Which statements are correct?
A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only
▶️ Answer/Explanation
✅ Answer: (A)
Question 31
Which type of reaction takes place when methane reacts with chlorine in the presence of ultraviolet light?
A. addition
B. cracking
C. polymerisation
D. substitution
▶️ Answer/Explanation
✅ Answer: (D)
Question 32
Iron is extracted from iron(III) oxide in the blast furnace.
Three steps in the process are listed.
- Carbon (coke) is completely oxidised.
- Iron(III) oxide is reduced.
- Carbon dioxide is reduced to carbon monoxide.
What is the correct order of the steps in the extraction of iron?
A. 1 → 2 → 3
B. 1 → 3 → 2
C. 2 → 1 → 3
D. 3 → 1 → 2
▶️ Answer/Explanation
Step 3: Carbon dioxide is reduced to carbon monoxide: \(\mathrm{CO_2 + C \rightarrow 2CO}\).
Step 2: Iron(III) oxide is reduced by carbon monoxide: \(\mathrm{Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2}\).
Correct order: 1 → 3 → 2.
✅ Answer: (B)
Question 33
Three different reactions that occur during the extraction of aluminium from purified bauxite are listed.
- \(\mathrm{Al^{3+} + 3e^- \rightarrow Al}\)
- \(\mathrm{C + O_2 \rightarrow CO_2}\)
- \(\mathrm{2O^{2-} \rightarrow O_2 + 4e^-}\)
Which reactions occur at the anode?
A. 1 and 2
B. 1 only
C. 2 and 3
D. 3 only
▶️ Answer/Explanation
At the anode (+), oxidation occurs. Reaction 3 (\(\mathrm{2O^{2-} \rightarrow O_2 + 4e^-}\)) is the oxidation of oxide ions at the anode. Reaction 2 (\(\mathrm{C + O_2 \rightarrow CO_2}\)) also occurs at the anode as the oxygen produced reacts with the carbon anodes, causing them to be regularly replaced.
Reaction 1 is reduction and occurs at the cathode (−).
✅ Answer: (C)
Question 34
Which statement about aqueous ethanoic acid is correct?
A. It reacts with magnesium to form oxygen gas.
B. It reacts with sodium carbonate to form carbon dioxide gas.
C. It turns red litmus paper blue.
D. It turns methyl orange yellow.
▶️ Answer/Explanation
(A) is false — ethanoic acid reacts with magnesium to form hydrogen gas, not oxygen.
(C) is false — acids turn blue litmus red, not the reverse.
(D) is false — acids turn methyl orange red/pink, not yellow (yellow is for alkalis).
✅ Answer: (B)
Question 35
The diagrams represent four monomers.
![]()
The monomers each react in a 1:1 ratio with the dicarboxylic acid shown.
![]()
How many of the four monomers shown can react with the dicarboxylic acid to form a polymer?
A. 1
B. 2
C. 3
D. 4
▶️ Answer/Explanation
✅ Answer: (B)
Question 36
Propene undergoes addition reactions with bromine, hydrogen and steam.
Which structures represent a product of these reactions?

A. 1 and 3
B. 1 and 4
C. 2 and 3
D. 3 and 4
▶️ Answer/Explanation
+ H₂ → propane (\(\mathrm{CH_3CH_2CH_3}\))
+ Br₂ → 1,2-dibromopropane (\(\mathrm{CH_3CHBrCH_2Br}\))
+ H₂O (steam) → mainly propan-2-ol (\(\mathrm{CH_3CH(OH)CH_3}\)) according to Markovnikov’s rule.
Option (D) shows the structures representing these products.
✅ Answer: (D)
Question 37
The structures of four compounds are shown.

Which compounds are members of the same homologous series?
A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 4
D. 2 and 4
▶️ Answer/Explanation
✅ Answer: (D)
Question 38
Which statement about ethanoic acid is correct?
A. Ethanol is reduced by bacteria to produce ethanoic acid.
B. Ethanoic acid reacts with magnesium to produce a salt of formula \(\mathrm{CH_3COOMg}\).
C. Ethanoic acid and methanol react in the presence of an acid catalyst to produce ethyl methanoate.
D. Ethanol reacts with acidified aqueous potassium manganate(VII) to produce ethanoic acid.
▶️ Answer/Explanation
(A) is false — ethanol is oxidised, not reduced.
(B) is false — the correct formula for magnesium ethanoate is \(\mathrm{(CH_3COO)_2Mg}\).
(C) is false — ethanoic acid + methanol produces methyl ethanoate, not ethyl methanoate.
✅ Answer: (D)
Question 39
Substance X contains one cation.
Two tests are completed on aqueous X.
- test 1: flame test
- test 2: addition of aqueous sodium hydroxide dropwise and then in excess
Which row shows a possible combination of observations for the tests?

▶️ Answer/Explanation
(A) Yellow flame = Na⁺, but Na⁺ gives no precipitate with NaOH.
(C) Light green flame is not characteristic of any common cation; green ppt. soluble in excess indicates Cr³⁺, but chromium gives no distinct flame colour.
(D) Red flame = Li⁺ or Ca²⁺ (orange-red), but red-brown ppt. indicates Fe³⁺, a mismatch.
✅ Answer: (B)
Question 40
A colourless mixture is separated by paper chromatography.
The steps below describe the method. These steps are not in the correct order.
- Remove the chromatography paper from the solvent when the solvent front is near the top of the paper.
- Place the chromatography paper in the solvent.
- Spray the chromatography paper with a locating agent.
- Place a spot of the mixture on the pencil line.
- Draw a pencil line at the bottom of the chromatography paper.
- Draw a pencil line to mark the position of the solvent front.
What is the correct order for these steps?
A. 3 → 5 → 6 → 4 → 2 → 1
B. 5 → 4 → 3 → 2 → 1 → 6
C. 3 → 5 → 4 → 1 → 2 → 6
D. 5 → 4 → 2 → 1 → 6 → 3
▶️ Answer/Explanation
Step 5: Draw a pencil line at the bottom of the chromatography paper (baseline).
Step 4: Place a spot of the mixture on the pencil line.
Step 2: Place the chromatography paper in the solvent (solvent level below the baseline).
Step 1: Remove the paper when the solvent front is near the top.
Step 6: Draw a pencil line to mark the position of the solvent front immediately.
Step 3: Spray with a locating agent to make colourless spots visible.
Order: 5 → 4 → 2 → 1 → 6 → 3.
✅ Answer: (D)
