# Which of the following relationship is not correct?

(a) In an exothermic reaction the enthalpy of product is less than that of the reactants
(b) $\Delta H_{fus} = \Delta H_{subl} - \Delta H_{vap}$
(c) A reaction for which $\Delta H^\circ$ < 0 and $\Delta S$ > 0 is possible at all temperatures.
(d) $\Delta H$ is less than $\Delta E$ for combustion of carbon to carbon dioxide.

Answer: $\Delta H$ is less than $\Delta E$ for combustion of carbon to carbon
In the formation of $CO_2$ from carbon on combustion,
$C(s) + O_2 (g) \longrightarrow CO_2(g)$
Since, $\Delta n_g = n_p - n_r$ and $\Delta H = \Delta E + \Delta n_gRT$
$\Delta n_g = 1 -1 = 0$
$\therefore \Delta H = \Delta E$