Question

The relationship between$\Delta$H and $\Delta$E for the reaction $PC{l}_3\left(g\right)+C{l}_2\left(g\right)\to PC{l}_5\left(g\right)$ is given as;

• A. $\Delta$H=$\Delta$E +RT
• B. $\Delta$H=$\Delta$ E - RT
• C. $\Delta$H =$\Delta$E - 2RT
• D. $\Delta$H =$\Delta$ E +2RT

Answer 1

Answer: (B)

$\Delta$H=$\Delta$ E - RT

$PC{l}_3\left(g\right)+C{l}_2\left(g\right)\to PC{l}_5\left(g\right)$
$\Delta n_g=1-1-1$
$=-1$
$\Delta H=\Delta E+\Delta n_{g}RT$
$\therefore \Delta H=\Delta E-RT$

Option B is correct.