Question

∆U° of combustion of CH4 (g)at certain temperature is -393kj/ mol.Then value of ∆H° is

1)0

2)<∆U°

3)>∆U°

4)=∆U°

Answer 1

Dear student,
In actual reaction of combustion of methane, water vapour or water in gaseous form is formed.
Thereby above solution is correct.

If in the reaction it is given as liquid
Then delta n= 1-2= -2
Hence delta H= delta N -2gRT
Therefore delta H< delta U
Option 2 is correct