Question
Equal volumes of molar hydrochloric acid and sulphuric acid are neutralised 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.
$$x = \frac{1}{2}y$$
C.
$$x = 2y$$
D.
$${\text{None of the above}}$$
Answer :
$$x = \frac{1}{2}y$$
Solution :
$$HCl + NaOH \to $$ $$NaCl + {H_2}O + x\,kcal$$
$${H_2}S{O_4} + 2NaOH \to $$ $$N{a_2}S{O_4} + 2{H_2}O + y\,kcal$$
$$1\,molar\,HCl $$ $$ = 1\,g{\text{ - equivalent of}}\,HCl$$
$$1\,molar\,{H_2}S{O_4}$$ $$ = 2\,g\,{\text{ - equivalent of}}\,{H_2}S{O_4}$$
$${\text{so,}}\,\,y = 2x\,\, \Rightarrow \,\,\,\,x = \frac{1}{2}y$$