Question

The amount of heat evolved on combustion of $10$ grams of benzoic acid is $10K.Cals$. The heat of combustion of Benzoic acid is:

• A. $-122K.Cals$
• B. $-112KCals$
• C. $-132K.Cals$
• D. $-92K,Cals$

Answer 1

The correct option is A $-122K.Cals$

Solution

Amount of heat evolved on combustion

of 10g of benzoic acid = 10K cals

Amount & 1 mole (122g) of combustion

of benzoic acid $\Rightarrow \frac{122}{10}\times 10$

$=122Kcals$

During the combustion of heat, heat is

evolved $\Rightarrow -122Kcals$