If bond enthalpies of $$N \equiv N,H - H$$ and $$N - H$$ bonds are $${x_1},{x_2}$$ and $${x_3}$$ respectively, $$\Delta H_f^ \circ $$ for $$N{H_3}$$ will be
A.
$${x_1} + 3{x_2} - 6{x_3}$$
B.
$$\frac{1}{2}{x_1} + \frac{3}{2}{x_2} - 3{x_3}$$
C.
$$3{x_3} - \frac{1}{2}{x_1} - \frac{3}{2}{x_2}$$
Releted MCQ Question on Physical Chemistry >> Chemical Thermodynamics
Releted Question 1
The difference between heats of reaction at constant pressure and constant volume for the reaction : $$2{C_6}{H_6}\left( l \right) + 15{O_{2\left( g \right)}} \to $$ $$12C{O_2}\left( g \right) + 6{H_2}O\left( l \right)$$ at $${25^ \circ }C$$ in $$kJ$$ is
$${\text{The}}\,\Delta H_f^0\,{\text{for}}\,C{O_2}\left( g \right),\,CO\left( g \right)\,$$ and $${H_2}O\left( g \right)$$ are $$-393.5,$$ $$-110.5$$ and $$ - 241.8\,kJ\,mo{l^{ - 1}}$$ respectively. The standard enthalpy change ( in $$kJ$$ ) for the reaction $$C{O_2}\left( g \right) + {H_2}\left( g \right) \to CO\left( g \right) + {H_2}O\left( g \right)\,{\text{is}}$$