Enthalpy of CH4 + (1/2) O2 arrow CH3OH is negative. If enthalpy of combustion of CH4 and CH3OH are x and y respectively, then which relation is correct

Question

Enthalpy of CH4 + (1/2) O2 arrow CH3OH is negative. If enthalpy of combustion of CH4 and CH3OH are x and y respectively, then which relation is correct (A) x > y (B) x < y (C) x = y (D) x ge y

Tardigrade Admin · Accepted Answer

CH 4( g )+(1/2) O 2( g ) arrow CH 3 OH ( l ) ∴ Δ H =-[(Δ H.. of combustion of ..CH 3 OH )]-[(Δ H.. of combustion of ..CH 4)] =-[(-y)-(-x)] =-[-y+x]=y-x Δ H = negative y-x= negative ∴ x > y

Q. Enthalpy of $C H_{4} + \frac{1}{2} O_{2} \to C H_{3} O H$ is negative. If enthalpy of combustion of $C H_{4}$ and $C H_{3} O H$ are x and y respectively, then which relation is correct

x > y

x < y

x = y

x $\geq$ y

$C H_{4} (g) + \frac{1}{2} O_{2} (g) \to C H_{3} O H (l)$
$∴ Δ H = - [(Δ H$ of combustion of
$C H_{3} O H)] - [(Δ H$ of
combustion of $C H_{4})]$
$= - [(- y) - (- x)]$
$= - [- y + x] = y - x$
$Δ H =$ negative
$y - x =$ negative
$∴ x > y$

Q. Enthalpy of CH4​+21​O2​→CH3​OH is negative. If enthalpy of combustion of CH4​ and CH3​OH are x and y respectively, then which relation is correct