Question

The enthalpy of a reaction at $273K$. is - $3.57KJ$. What will be the enthalpy of reaction at $373K$ if $\Delta C_p=zero$?

• A. $-3.57$
• B. zero
• C. $-3.57\times \frac{373}{273}$
• D. $-375$.

Answer 1

The correct option is A $-3.57$

Solution:- (A) $-3.57$

By Kirchhoff's law,

$\Delta C_P=\frac{\Delta H_2-\Delta H_1}{T_2-T_1}$

Given that:-

$\Delta C_P=0$

$\Delta H_2-\Delta H_1=0$

$\Rightarrow \Delta H_2=\Delta H_1=-3.57KJ$

Hence the enthalpy of reaction at $373K$ is $-3.57KJ$.