The enthalpies of combustion of `C_(("graphite")) and C_(("diamond"))` are `-393.5 and -395.4kJ//mol` respectively. The enthalpy of conversion of `C_(("graphite"))` to `C_(("diamond"))` in kJ/mol is:

Options

A. -1.9 kJ/mole
B. `+ 1 .9` kJ/mole
C. 788.7 kJ/mole
D. -788.7 kJ/mole

Answer

B

Explanation

Given :
(i) `C("graphite") +O_(2) rarr CO_(2)" "Delta H=-393.5 kJ`
(ii) `C("diamond") +O_(2) rarr CO_(2)" Delta H =-395.4 kJ`
Aim: `C("graphite") rarr C("diamond")`
Equation (i) - equation (ii) gives the required results.