MI Prelim H2 Chem P1 QP ans for exchange

Class Adm No Candidate Name: This question paper consists of 12 printed pages and 2 blank pages. 2025 Preliminary Examination Pre-University 3 H2 CHEMISTRY 9729/01 Paper 1 Multiple Choice 17 Sep 2025 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Do not turn over this question paper until you are told to do so Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, class and admission number in the spaces provided at the top of this page and on the Multiple Choice Answer Sheet provided. There are thirty questions on this paper. Answer ALL questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the Multiple Choice Answer Sheet provided. Read the instructions on the Multiple Choice Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this question paper. The use of an approved scientific calculator is expected, where appropriate. FOR EXAMINER’S USE TOTAL (30 marks) H

2 1 Sulfur dioxide is a preservative that can be found in small amount in wines. The sulfur dioxide content in wine can be determined through back titration. A 25 cm3 sample of wine is reacted with 30.0 cm3 of 0.01 mol dm−3 of excess aqueous iodine, oxidising the sulfur dioxide in the wine to sulfate, SO42−, in the process. SO2 + I2 + 2H2O ⟶ SO42− + 4H+ + 2I− The unreacted iodine requires exactly 2 4.80 cm 3 of 0.02 mol dm −3 sodium thiosulfate for complete reaction. 2S2O32− + I2 ⟶ 2I− + S4O62− What is the concentration of sulfur dioxide, in mol dm−3, in the wine? A 2.08  10−3 B 2.48  10−3 C 9.92  10−3 D 2.77  10−2 2 Which of the following contains approximately the same number of the stated particles as there are atoms in 18.0 g of water? 1 number of ions in 142.1 g of sodium sulfate, Na2SO4 2 number of molecules in 6.0 g of hydrogen gas 3 number of neutrons in 6.0 g of carbon-12 A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 3 Ions of the two most common isotopes of zinc are shown below: Zn30 64 2+ Zn30 66 2+ Which of the following statements is correct? A Both these Zn2+ ions have the same number of electrons but different number of protons. B Both these Zn2+ ions have the same electronic configuration 1s22s22p63s23p63d84s2. C The Zn30 64 2+ ion has fewer neutrons in its nucleus than the Zn30 66 2+ ion. D The Zn30 66 2+ ion will be deflected more than the Zn30 64 2+ ion in an electric field of the same strength.

3 [Turn over 4 The successive ionisation energies (IE) of two elements, W and X, are given below. IE / kJ mol−1 1st 2nd 3rd 4th 5th 6th 7th 8th W 1090 2350 4610 6220 37800 47000 - - X 1251 2298 3822 5158 6542 9362 11018 33604 What is the likely formula of the compound that is formed when W reacts with X? A WX B W2X3 C WX4 D W4X 5 Which of following statements are incorrect? 1 Any covalent compound that contains both hydrogen and oxygen in its molecule can form intermolecular hydrogen bond. 2 Ionic compounds can be distinguished from metals by their electrical conductivity in the liquid states. 3 All substances with covalent bonding have poor electrical conductivity. A 1 and 2 B 2 and 3 only C 1 and 3 only D 1, 2 and 3 6 Which of the following species contains the smallest bond angle? A N2H4 B BrF5 C XeF2 D SO2 7 The table below shows the standard thermodynamic values for the synthesis of hydrogen chloride: H2(g) + Cl2(g) ⟶ 2HCl(g) H⦵ −184.6 kJ mol−1 S⦵ +20.0 J K−1 mol−1 What is the value of G⦵ of the reaction? A +179 kJ mol−1 B −179 kJ mol−1 C −185 kJ mol−1 D −191 kJ mol−1

4 8 Which of the following has the same value as the standard enthalpy change of formation of carbon monoxide? A ½Hc⦵ (C(graphite)) B Hf⦵ (CO2) – Hc⦵ (C(graphite)) C Hf⦵ (CO2) – ½Hc⦵ (C(graphite)) D Hc⦵ (C(graphite)) – Hc⦵ (CO) 9 Which of the following graphs shows the correct relationship between the density of a gas ( ) against temperature (T) for an ideal gas under constant pressure? A B C D  T / K  T / K  T / K  T / K

5 [Turn over 10 Steam reforming of methane is the main source of production of hydrogen in the industry. There are two steps in the process, both being in equilibrium in closed systems: Step 1 CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g) H = +210 kJ mol−1 Step 2 CO(g) + H2O(g) ⇌ CO2(g) + H2(g) H = −42 kJ mol−1 Which statement about Step 1 and Step 2 is correct? A Increasing the pressure increases the equilibrium constant for Step 2. B Increasing the temperature increases the equilibrium constant for Step 1. C Addition of a catalyst increases both the yield and rate of production of hydrogen gas. D Increasing the temperature decreases the rate constant for the forward reaction in Step 2. 11 The Contact process is an industrial process to produce sulfuric acid. One of the reactions involved is the reaction of sulfur dioxide with oxygen. 2SO2(g) + O2(g) ⇌ 2SO3(g) H < 0 Which of the following pair of changes will increase the amount of SO3 present at equilibrium? temperature pressure A increase increase B increase decrease C decrease increase D decrease decrease

6 12 Zinc oxide reacts with hydrogen according to the following equation. ZnO(s) + H2(g) ⇌ Zn(s) + H2O(g) At temperature T and a total pressure of 10 atm, it is found that initial amounts of 1 mole of zinc oxide and hydrogen gas each produce 0.01 mole of zinc and steam at equilibrium. What is the approximate value of Kp at temperature T? A 10−4 B 10−2 C 10 D 100 13 The reaction between hydrogen peroxide and acidified iodide ions produces iodine. This reaction can be represented by the following equation: H2O2(aq) + 2H+(aq) + 2I−(aq) ⟶ I2(aq) + 2H2O(l) Investigation of the reaction kinetics revealed that the rate equation takes the form: rate = k[H2O2][I−] The results of two separate series of experiments are displayed in Graph A and Graph B. Graph A Graph B Which of the following shows the correct labeling of the x -axis for Graph A and y-axis for Graph B? x-axis for Graph A y-axis for Graph B A [H2O2][I−] / mol2 dm-6 [H+] / mol dm-3 B [I−][H+] / mol2 dm-6 [I2] / mol dm-3 C [H2O2] / mol dm-3 [I−]/ mol dm-3 D [H+] / mol dm-3 [H2O2] / mol dm-3

7 [Turn over 14 The reaction between substances A and B is found to follow the rate law rate = k[A]m[B] where k is the rate constant and has units of mol–2 dm6 s–1. Two experiments to study the kinetics of this reaction were carried out and the data obtained are tabulated below. Experiment Initial [A] / mol dm–3 Initial [B] / mol dm–3 Initial rate / mol dm–3 s–1 1 0.040 0.080 R 2 0.020 y R 2 What is the value of y in experiment 2? A 0.020 B 0.040 C 0.160 D 0.320 15 Methylcyclohexane can react with chlorine gas to form monochlorinated products. methylcyclohexane How many different constitutional isomers of monochlorinated products can be formed? A 4 B 5 C 6 D 7

8 16 Which molecules rotate plane polarised light? 1 2 3 4 A 1 and 2 only B 3 and 4 only C 1, 3 and 4 only D 1, 2, 3 and 4 17 Which of the following reagents can be used to distinguish between the two compounds below? 1 alkaline I2(aq) 2 neutral FeCl3(aq) 3 Na2CO3(aq) 4 2,4-dinitrophenylhydrazine A 1 and 3 only B 2 and 4 only C 1, 2 and 4 only D 1, 2, 3 and 4

9 [Turn over 18 Aldosterone is a hormone essential for sodium conservation in t