In which of the following reactions, `Delta H` is greater than `Delta U` ?

Options

A. `N_(2(g))+3H_(2(g)) rarr 2NH_(3(g))`
B. `PCl_(5(g))rarr PCl_(3(g))+Cl_(2(g))`
C. `CH_(4(g))+2O_(2(g)) rarr CO_(2(g))+2H_(2)O_((l))`
D. `HCl_((aq))+NaOH_((aq)) rarr NaCl_((aq))+H_(2)O_((aq))`

Answer

B

Explanation

`Delta H= Delta U + Delta nRT`
In the reaction `PCl_(5(g))rarrPCl_(3(g))+Cl_(2(g))`
`Delta n=(1+1)-1=1`
`therefore Delta H = Delta U +RT therefore Delta H gt Delta U`