StudyWithSmile — free flashcards, quizzes and exam practice for school students

Chemistry — Model Question Paper 1

Chemistry · Kerala SSLC (Class 10) · English Medium · SSLC 2027 pattern · English Medium · 40 marks · 90 min + 15 min cool-off

Section A

Questions 1–4 carry 1 score each. Answer all.

  1. A gas occupies 2 L at 300 K. It is heated to 450 K while its pressure is kept constant. What is its new volume? [1 mark]
    • 1.33 L
    • 2 L
    • 3 L
    • 4.5 L
  2. Assertion (A): In a zinc–copper galvanic cell, the zinc rod becomes thinner as the cell works. Reason (R): Zinc is more reactive than copper, so zinc atoms lose electrons and pass into the solution as Zn²⁺ ions. Which of the following is correct? [1 mark]
    • Both (A) and (R) are correct, and (R) is the correct explanation of (A).
    • Both (A) and (R) are correct, but (R) is not the correct explanation of (A).
    • (A) is correct, but (R) is not correct.
    • (A) is not correct, but (R) is correct.
  3. Match column A with column B. A (X) CH₃–CO–CH₃ (Y) CH₃–O–CH₃ (Z) CH₃–CH₂–CHO B (i) Propanal (ii) Methoxymethane (iii) Propanone (iv) Propan-1-ol Choose the correct combination. [1 mark]
    • X–(i), Y–(ii), Z–(iii)
    • X–(iii), Y–(ii), Z–(i)
    • X–(iii), Y–(iv), Z–(i)
    • X–(iv), Y–(ii), Z–(i)
  4. Some statements about the industrial manufacture of ammonia (Haber process) are given. (i) Sponge iron is used as the catalyst. (ii) Increasing the pressure increases the amount of ammonia formed. (iii) The forward reaction is endothermic, so raising the temperature increases the yield of ammonia. Which of the following is correct? [1 mark]
    • Statements (i), (ii) and (iii) are correct.
    • Statements (i) and (iii) are correct, but (ii) is not correct.
    • Statements (ii) and (iii) are correct, but (i) is not correct.
    • Statements (i) and (ii) are correct, but (iii) is not correct.

Section B

Questions 5–11 carry 2 scores each. Two questions from 5 to 11 have a choice — answer (A) or (B).

  1. The subshell electron configuration of an element X ends in 3d⁵ 4s¹. (The symbol is not real.) [2 marks]
    • (a) Write the complete subshell electron configuration of X and find its atomic number.
    • (b) To which block and group does X belong?
  2. When decane is heated strongly in the absence of air, one of the reactions that takes place is: C₁₀H₂₂ → C₈H₁₈ + P [2 marks]
    • (a) Write the molecular formula and the IUPAC name of P.
    • (b) Name this process. How can this process help reduce pollution?
  3. Copper used for electrical wiring must be 99.99% pure. Blister copper is purified by electrolytic refining, using copper sulphate solution mixed with dilute sulphuric acid as the electrolyte. [2 marks]
    • (a) What is used as the anode, and what is used as the cathode?
    • (b) Write the chemical equation of the reaction that takes place at the cathode.
  4. (A) A sample of carbon dioxide has a mass of 22 g. (Atomic mass: C = 12, O = 16) [2 marks]
    • (a) How many moles of CO₂ are present in the sample?
    • (b) What volume will this sample occupy at STP?

    OR

    (B) A balloon holds 44.8 L of oxygen gas (O₂) at STP. (Atomic mass: O = 16)

  5. Molten sodium chloride is electrolysed using graphite electrodes. [2 marks]
    • (a) Write the chemical equation of the reaction at the anode. Which product is formed there?
    • (b) Solid sodium chloride does not conduct electricity, but molten sodium chloride does. Why?
  6. (A) The structural formula of a compound is CH₃–CH₂–CH₂–OH. [2 marks]
    • (a) Write the structural formula and the IUPAC name of its position isomer.
    • (b) Write the structural formula and the IUPAC name of a functional group isomer of this compound.

    OR

    (B) The structural formula of a hydrocarbon is CH₃–CH(CH₃)–CH₂–CH₃.

  7. Aqueous solutions of three salts, NH₄Cl, Na₂CO₃ and KNO₃, are tested with blue litmus paper. [2 marks]
    • (a) Which solution turns blue litmus red?
    • (b) Give the reason.

Section C

Questions 12–17 carry 3 scores each. Two questions from 12 to 17 have a choice — answer (A) or (B).

  1. Observe the reactions given below. (i) CH≡CH + H₂ → A (nickel catalyst) (ii) A + H₂ → B (nickel catalyst) (iii) B + Cl₂ → C + HCl (in sunlight) [3 marks]
    • (a) Write the structural formula and IUPAC name of A.
    • (b) Name the type of reaction in (i) and in (iii).
    • (c) Write the structural formula and IUPAC name of C.
  2. (A) The positions of two elements in the periodic table are given. (The symbols are not real.) Element X: Period 3, Group 17 Element Y: Period 4, Group 2 [3 marks]
    • (a) Write the subshell electron configuration of X.
    • (b) Write the n and l values of the outermost subshell of Y.
    • (c) Write the chemical formula of the compound formed between X and Y.

    OR

    (B) Cobalt (Co) has atomic number 27. It forms the compound CoCl₂.

  3. The graph shows how the volume of a fixed mass of a gas changes with its temperature (in kelvin) at constant pressure. [3 marks]
    • (a) Which gas law does this graph represent? State the law.
    • (b) A balloon contains 3 L of air at 27 °C. Keeping the pressure constant, it is warmed to 127 °C. Find its new volume.
  4. A galvanic cell is set up as shown in the figure. (Reactivity: Mg > Zn > Cu) [3 marks]
    • (a) Which electrode, A or B, is the anode? In which direction do electrons flow in the external wire?
    • (b) Write the chemical equation of the reaction at the cathode.
    • (c) If the Mg rod and MgSO₄ solution are replaced by a Zn rod and ZnSO₄ solution, will the voltmeter reading increase or decrease? Why?
  5. (A) Different ores are concentrated by different methods. [3 marks]
    • (a) Galena (PbS) is concentrated by froth floatation. Why is this method suitable for it?
    • (b) Name the method used to concentrate bauxite and the substance used in it.
    • (c) Magnetite (Fe₃O₄) can be concentrated by magnetic separation. What property makes this possible?

    OR

    (B) Blocks of zinc or magnesium are fixed to the steel hulls of ships.

  6. In the Contact process, sulphur dioxide is converted to sulphur trioxide: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) + heat [3 marks]
    • (a) Name the catalyst used in this step.
    • (b) According to Le Chatelier's principle, how will increasing the pressure affect the amount of SO₃? Why?
    • (c) Why is SO₃ dissolved in concentrated sulphuric acid instead of directly in water?

Section D

Question 18 carries 4 scores. It has a choice — answer (A) or (B).

  1. (A) Some hints about an organic compound P are given. • It has four carbon atoms in a straight chain. • It is an alcohol with the –OH group on the second carbon atom. [4 marks]
    • (a) Write the structural formula and IUPAC name of P.
    • (b) Write the structural formula and IUPAC name of a position isomer of P.
    • (c) Write the molecular formula of P. Write the structural formula and IUPAC name of an ether that is a functional group isomer of P.
    • (d) Write the structural formula of another ether that is a metamer of the ether you wrote in (c). Name it.

    OR

    (B) Aluminium is extracted from bauxite by the Hall–Héroult process.

Sign in free to see model answers and marking points, and check your score.

All Chemistry chapters and papers