Question

Assertion :For a reaction ,

$2N{H}_3\left(g\right)\to N_2\left(g\right)+3H_2\left(g\right)$

$\Delta H>\Delta E$.

Reason: Enthalpy change is always greater than internal energy change.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is correct.

Answer 1

The correct option is C Assertion is correct but Reason is incorrect.

For given reaction $\Delta H>\Delta E$

because $\{\Delta H=\Delta E+\Delta nRT\}$.

In this reaction, $\Delta n_{\left(g\right)}$ is $\left[\right(3+1)-2]=+2$

So, $\Delta H>\Delta E$.

Thus, the Assertion is correct.

In some cases, the enthalpy change may be less than internal energy change (in these cases $\Delta n_{\left(g\right)}$, is negative).

So, Reason is incorrect.

Hence, option C is correct