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The heat liberated when 1.89 g of benzoi...

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

A

771.1 kcal

B

871.2 kcal

C

881.1 kcal

D

981.1 kcal

Text Solution

Verified by Experts

The correct Answer is:
A
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
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