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

Answer

C

Explanation

`C_6H_5COOH(s)+15/2O_2(g) rarr 7 CO_2(g)+3H_2 O(l)`
`Delta n_g =n_p-n_r = 7-(15)/(2)= (-1)/(2)`
`q_p = q_V + Deltan_g RT =- 321.30 + ((-1)/(2)) 300 R `
`= -321.30 -150 R.`