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Temperature rise when an acid and NaOH solution are mixed, from the enthalpy of neutralisation

This type of question, asked 3 times: 2021 Paper 17, 2021 Paper 20, 29 Jul 2022. All 3 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    2021 Paper 17

    52
    When 400 mL400\text{ }mL of 0.2MH2SO40.2MH_{2}SO_{4} solution is mixed with 600 mL600\text{ }mL of 0.1MNaOH0.1MNaOH solution, the increase in temperature of the final solution is ____\_\_\_\_ ×10−2 K\times10^{- 2}\text{ }K. (Round off to the nearest integer). [Use: H+(aq)+OH−(aq)→H2OH^{+}(aq) +OH^{-}(aq) \rightarrow H_{2}O :
     ΔrH=−57.1 kJ mol−1]\left. \ \Delta_{r}H = - 57.1\text{ }kJ{\text{ }mol}^{- 1} \right\rbrack
    Specific heat of H2O=4.18 J K−1 g−1H_{2}O = 4.18\text{ }J{\text{ }K}^{- 1}{\text{ }g}^{- 1} density of H2O=1.0 g cm−3H_{2}O = 1.0\text{ }g{\text{ }cm}^{- 3} Assume no change in volume of solution on mixing.

  2. Question 2

    2021 Paper 20

    58
    200 mL200\text{ }mL of 0.2MHCl0.2MHCl is mixed with 300 mL300\text{ }mL of 0.1MNaOH0.1MNaOH. The molar heat of neutralization of this reaction is −57.1 kJ- 57.1\text{ }kJ. The increase in temperature in  ∘C\ ^{\circ}C of the system on mixing is x×10−2x \times10^{- 2}. The value of xx is ____\_\_\_\_. (Nearest integer) [Given: Specific heat of water =4.18 J g−1 K−1= 4.18\text{ }J{\text{ }g}^{- 1}{\text{ }K}^{- 1} Density of water  =1.00 g cm−3]\left. \ = 1.00\text{ }g{\text{ }cm}^{- 3} \right\rbrack (Assume no volume change on mixing)

  3. Question 3

    29 Jul 2022

    54
    When 600 mL600\text{ }mL of 0.2MHNO30.2MHNO_{3} is mixed with 400 mL400\text{ }mL of 0.1MNaOH0.1MNaOH solution in a flask, the rise in temperature of the flask is ____\_\_\_\_ ×10−2 ∘C\times10^{- 2}\ ^{\circ}C. (Enthalpy of neutralisation =57 kJ mol−1= 57\text{ }kJ{\text{ }mol}^{- 1} and Specific heat of water =4.2JK−1 g−1= 4.2JK^{- 1}{\text{ }g}^{- 1} ) (Neglect heat capacity of flask)