Question

Equal volume of molar HCl and ${H_2}S{O_4}$ are neutralized by dilute NaOH solution and x Kcal and y Kcal of heat are liberated respectively. Which of the following is true?
A. x = y
B. $x = \dfrac{y}{2}$
C. $x = \dfrac{y}{3}$
D. x = 2y

Answer 1

The reaction taking place between the acid and base is known as neutralization reaction and heat is evolved during the reaction. As in sulphuric acid two mole of hydrogen is present the heat evolved will be double the heat evolved by hydrochloric acid.

Complete step by step answer:
The neutralization reaction is defined as the reaction taking place between acidic compounds and a basic compound and as a result the main product formed is salt with the elimination of water and heat.
The general neutralization reaction is shown below.
$Acid + Base \to salt + water$
In this reaction acid reacts with base to form salt as a main product and water as a side product.
As heat is liberated during the neutralization reaction, therefore the reaction is considered as an exothermic reaction.
The reaction between hydrochloric acid and sodium hydroxide is shown below.
$HCl + NaOH \to NaCl + {H_2}O$
In this reaction one mole of hydrochloric acid reacts with one mole of sodium hydroxide to give sodium chloride and water.
The reaction between sulphuric acid and sodium hydroxide is shown below.
${H_2}S{O_4} + 2NaOH \to N{a_2}S{O_4} + 2{H_2}O$
In this reaction, one mole of sulphuric acid reacts with two mole of sodium hydroxide to form one mole of sodium sulphate and two mole of water.
The heat liberated by reacting hydrochloric acid and sodium hydroxide is x K cal.
The heat liberated by reacting sulphuric acid and sodium hydroxide is y K cal.
In sulphuric acid ${H_2}S{O_4}$, two mole of hydrogen is present there the heat evolved will be double the heat evolved by hydrochloric acid HCl.
The equation is given as shown below.
Heat released by ${H_2}S{O_4}$= $2 \times$ heat released by HCl
Substitute the values in the above equation.
$y = 2x$
$\Rightarrow x = \dfrac{y}{2}$

So, the correct answer is Option B.

Note: It is given that equal volume of molar HCl and ${H_2}S{O_4}$ are neutralized by dilute NaOH solution but the volume does not play an important role in the liberation of heat. It depends on the mole of hydrogen present.