When equal volume of $1 \mathrm{~M} \mathrm{~HCl}$ and $1 \mathrm{~M} \mathrm{~H}_2 \mathrm{SO}_4$ are separately neutralised by excess volume of $1 \mathrm{M}$ $\mathrm{NaOH}$ solution. $x$ and $y \mathrm{~kJ}$ of heat is liberated respectively. The value of $y / x$ is __________.
Answer (integer)
2
Solution
<p>To solve this problem, we need to understand the concept of neutralization reactions and the heat evolved during these reactions.
<p>When an acid and a base react, they undergo a neutralization reaction to produce water and a salt. The heat released in this process is known as the enthalpy of neutralization.</p>
<p>Consider the neutralization of hydrochloric acid (HCl) and sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) by sodium hydroxide (NaOH). The balanced chemical equations for these neutralizations are:</p>
<p>$\mathrm{HCl} + \mathrm{NaOH} \rightarrow \mathrm{NaCl} + \mathrm{H_2O}$</p>
<p>$\mathrm{H_2SO_4} + 2\mathrm{NaOH} \rightarrow \mathrm{Na_2SO_4} + 2\mathrm{H_2O}$</p>
<p>For the first reaction, each mole of HCl reacts with one mole of NaOH, releasing a certain amount of heat (let's denote this amount by $ x $ kJ). For the second reaction, each mole of H<sub>2</sub>SO<sub>4</sub> reacts with two moles of NaOH. Since we are given equal volumes and molarities of HCl and H<sub>2</sub>SO<sub>4</sub>, we can infer that one mole of H<sub>2</sub>SO<sub>4</sub> will produce twice the heat of one mole of HCl because it produces double the amount of water.
</p>
<p>Thus, the heat evolved in the neutralization of H<sub>2</sub>SO<sub>4</sub> by NaOH (denoted as $ y $ kJ) will be approximately twice that of HCl. Therefore, $ y = 2x $.
<p>
<p>Therefore, the value of $\frac{y}{x}$ is:</p>
</p>
<p>$\frac{y}{x} = \frac{2x}{x} = 2$</p>
<p>So, the value of $\frac{y}{x}$ is 2.</p>
</p>
About this question
Subject: Chemistry · Chapter: Thermodynamics · Topic: Zeroth and First Law
This question is part of PrepWiser's free JEE Main question bank. 110 more solved questions on Thermodynamics are available — start with the harder ones if your accuracy is >70%.