Question

For the reactions,
(i) $H_2\left(g\right)+{Cl}_2\left(g\right)=2HCl\left(g\right)+x$ $kJ$
(ii) $2HCl\left(g\right)=H_2\left(g\right)+{Cl}_2\left(g\right)-y$ $kJ$
which one of the following statements is correct?

• A. $x-y>0$
• B. $x-y<0$
• C. $x-y=0$
• D. None of these

Answer 1

The correct option is C $x-y=0$

Since 1${}^{st}$ reaction is opposite of the 2${}^{nd}$ reaction.
So, on adding both reactions we will get,
$x-y=0$
Hence, answer is option $C$.