Consider the reaction, `N_(2) + 3H_(2) rarr 2NH_(3)` carried out at constant temperature and pressure. If `Delta H and Delta U` are the enthalpy and internal energy changes for the reaction, which of the following expressions is true?

Options

A. `Delta H = 0`
B. `Delta H= Delta U`
C. `Delta H lt Delta U`
D. `Delta H gt Delta U`

Answer

C

Explanation

At constant P or T
`Delta H= Delta U + Delta n_(g) RT rArr Delta n_(g)= n_(p)- n_(R) =2-4= -2`
`therefore Delta H lt Delta U`