The following results were obtained from a neutralisation reaction between 1 mol dm⁻³ hydrochloric acid and 1 mol dm⁻³ sodium hydroxide. This experiment was carried out to measure the heat of neutralisation of hydrochloric acid. The temperature rise which occurred during the reaction was recorded.

Volume of sodium hydroxide used = 50 cm³

Volume of acid used = 50 cm³

Temperature rise = 5 °C

(Density of water = 1 g cm⁻³)

Heat energy = mass of × 4.2 × temperature given out water/g J g⁻¹ °C⁻¹ rise/°C during reaction

a. Write a balanced chemical equation for the reaction.

b. What mass of solution was warmed during the reaction?

c. How much heat energy was produced during the reaction?

d. How many moles of hydrochloric acid were involved in the reaction?

e. How much heat would be produced if 1 mole of hydrochloric acid had reacted? (This is the heat of neutralisation of hydrochloric acid.)

f. The heat of neutralisation of hydrochloric acid is −57 kJ mol⁻¹. Suggest two reasons why there is a difference between this and your calculated value.