Question

Formation of ammonia is shown by the reaction,
$N_{2\left(g\right)}+3H_{2\left(g\right)}\to 2N{H}_{3\left(g\right)}$; ${\Delta }_r{H}^{\circ }=-91.8kJmo{l}^{-1}$
What will be the enthalpy of reaction for the decomposition of $N{H}_3$ according to the reaction?
$2N{H}_{3\left(g\right)}\to N_{2\left(g\right)}+3H_{2\left(g\right)};{\Delta }_r{H}^{\circ }=?$

• A. $-91.8kjmo{l}^{-1}$
• B. $+91.8kjmo{l}^{-1}$
• C. $-45.9kjmo{l}^{-1}$
• D. $+45.9kjmo{l}^{-1}$

Answer 1

Answer: (B)

The sign of $\Delta H$ is reversed.