Question

For the reactions (i) $H_2\left(g\right)+C{l}_2\left(g\right)⟶2HCl\left(g\right)+xKJ$
(ii) $H_2\left(g\right)+C{l}_2\left(g\right)⟶2HCl\left(l\right)+yKJ$


Which of the following statements is correct?

• A. x>y
• B. x<y
• C. x-y=0
• D. x=y

Answer 1

The correct option is B

x<y

(i) $H_2\left(g\right)+C{l}_2\left(g\right)⟶2HCl\left(g\right)+xKJ$
Say $H_2\left(g\right)$ reacts with $C{l}_2\left(g\right)$ to give 2 moles of HCl(g) with the release of x KJ of heat.

Now but the second reaction states that instead of HCl(g) we get HCl(l)

To convert HCl(g) $⟶$ HCl(l) heat is absorbed to make it condense to the liquid form.
Therefore y > x