The heat liberated when `1.89 g` of benzoic acid is burnt in a bomb calorimeter at `25^(@)C` increases the temperture of `18.94 kg` of water by `0.632 ^(@)C`. If the specific heat of water at `25^(@)C` is `0.998 cal//g "deg"`, the value of the heat of combustion of benzoic acid is

Options

A. 771.1 kcal
B. 871.2 kcal
C. 881.1 kcal
D. 981.1 kcal

Answer

A

Explanation

Heat evolved from 1.89q. of benzoic acid `(C_(6)H_(5)COOH)= 18.94 xx 10^(3) xx 0.632 xx 0.998` cal
Combustion heat of benzoic acid (molecular mass =122) per mole
`=(18.94 xx 10^(3) xx 0.632 xx 0.998 xx 122)/(1.89)` cal = 771.1 kcal