Question

When 0.2 g of butan-1-ol was burnt in a suitable apparatus,
the heat evolved was sufficient to raise the temperature
of 200 g of water by 5°C. Then what will be enthalpy of combustion of butan-1-ol in kcal/mol ?

Note :-
Molar mass of butan-1-ol is 74​

Answer 1

Answer:

ANSWER

Solution:- (D) 370

Heat required to raise the temperature of 200g water by 5℃(q)=m.c.ΔT

whereas,

m= mass of water =200g

c= specific heat of water =1Cal−g/℃

ΔT=5℃

∴q=200×1×5=1 kcal

Heat liberated by 0.2g of 1-butanol on burning =1 kcal

∴ Heat liberated by 1 mole of 1-butanol (74g)=

0.2

1

×74=370 kcal

Hence the heat liberated is 370 kcal.