The heat of combustion of solid benzoic acid at constant volume is `-321.30 kJ` at `27^(@)C`. The heat of combustion at constant pressure is

Options

A. `-321.30-300R`
B. `-321.30+300R`
C. `-321.30-150R`
D. `-321.30+900R`

Answer

C

Explanation

`C_(6)H_(5)COOH(s)+(15)/(2)O_(2)(g)to7CO_(2)(g)+3H_(2)O(l),Deltan_(g)=n_(p)-n_(r)=7-(15)/(2)=(-1)/(2)`
`q_(p)=q_(v)+Deltan_(g)RT`
`=-321.30+(-(1)/(2))300R`
`=-321.30-150R`