The heat liberated when 1.5 g benzoic acid is burnt in bomb calorimeter at 25°C increases thetemperature of 17.27 kg of water by 0.55°C. Theheat of combustion of benzoic acid is(Specific heat of water at 25°C is 0.998 calg-ideg- 1)670 kcal/mol981 kcal/mol840 kcal/mol771 kcal/mol

The heat liberated when 1.5 g benzoic acid is burnt in bomb calorime

1.	The heat liberated when 1.5 g benzoic acid is burnt in bomb calorimeter at 25°C increases thetemperature of 17.27 kg of water by 0.55°C. Theheat of combustion of benzoic acid is(Specific heat of water at 25°C is 0.998 calg-ideg- 1)670 kcal/mol981 kcal/mol840 kcal/mol771 kcal/mol
Answer» Mass of benzoic acid = 1.89 gTemperature OOF bomb calorimeter= 25 0 C=298KMass of water (m) =18.94 kg=18940 gIncrease in temperature (Δt)=0.632 0 CSPECIFIC heat of water (s) = 0.998 CAL/g-degHeat GAINED by water or heat liberated by benzoic acid(Q)=msΔt=18940×0.998×0.632=11946.14cal Since, 1.89 g of acid, liberates 11946.14 cal of heat.therefore heat liberated by 122 g (mol.wt of benzoic acid) of acid = 1.8911946.14×122 =771126.5cal≈771.1kcalHence, the correct option is C.