Enthalpy of combustion of methane and ethane are -210 kcal / mol and -368 kcal / mol respectively. The enthalpy of combustion of decane is

Question

Enthalpy of combustion of methane and ethane are -210 kcal / mol and -368 kcal / mol respectively. The enthalpy of combustion of decane is (A) -158 kcal (B) -1632 kcal (C) -1700 kcal (D) Data is incomplete

Tardigrade Admin · Accepted Answer

Given, CH 4+2 O 2 longrightarrow CO 2+2 H 2 O Δ H=-210 kcal / mol ...(i) C 2 H 6+(7/2) O 2 longrightarrow 2 CO 2+3 H 2 O Δ H=-368 kcal / mol ...(ii) On subtracting Eq (i) from Eq (ii), we get CH 2+(3/2) O 2 longrightarrow CO 2+ H 2 O Δ H=-158 kcal / mol ∴ Enthalpy of combustion of one CH 2 unit =-158 kcal / mol Δ H text comb ( C 10 H 22)=Δ H text comb ( CH 4)+9 × Δ H text comb ( CH 2) =-210+(9 ×-158) =-1632 kcal

Q. Enthalpy of combustion of methane and ethane are −210kcal/mol and −368kcal/mol respectively. The enthalpy of combustion of decane is

-158 kcal

-1632 kcal

-1700 kcal

Data is incomplete

Q. Enthalpy of combustion of methane and ethane are $- 210 k c a l / m o l$ and $- 368 k c a l / m o l$ respectively. The enthalpy of combustion of decane is