Given: 2C(s) + 2O2 (g) - 2CO2 (g) ; Δ H = -787 kJ H2 (g) + (1/2) O2(g) - H2O(ℓ ) ; Δ H = - 286 kJ C2H2 (g) + 2 (1/2) O2 (g) → 2CO2 (g) + H2O(ℓ) ; Δ H = - 1310 kJ The heat of formation of acetylene is

Question

Given: 2C(s) + 2O2 (g) -> 2CO2 (g) ; Δ H = -787 kJ H2 (g) + (1/2) O2(g) -> H2O(ℓ ) ; Δ H = - 286 kJ C2H2 (g) + 2 (1/2) O2 (g) → 2CO2 (g) + H2O(ℓ) ; Δ H = - 1310 kJ The heat of formation of acetylene is (A) -1802 kJ (B) +1802 kJ (C) +237 kJ (D) -800 kJ

Tardigrade Admin · Accepted Answer

2 C (s)+2 O 2(g) longrightarrow 2 CO 2(g) ; Δ H =-787 kJ ldots (i) H 2(g)+(1/2) O 2(g) longrightarrow H 2 O (l) ; Δ H =-286 kJ ldots (ii) C 2 H 2(g)+2 (1/2) O 2(g) longrightarrow 2 CO 2(g)+ H 2 O (l) Δ H=-1310 kJ ldots (iii) Add the Eqs. (i) and (ii) and subtract Eq. (iii) from them. 2 C + H 2 longrightarrow C 2 H 2-787-286+1310 2 C + H 2 longrightarrow C 2 H 2-1073+1310 2 C + H 2 longrightarrow C 2 H 2+237 Hence, the heat of formation of acetylene is + 237 kJ.

Q. Given: 2C(s)+2OX2​(g)​2COX2​(g);ΔH=−787kJ HX2​(g)+21​ OX2​(g)​HX2​O(ℓ);ΔH=−286kJ CX2​HX2​(g)+221​ OX2​(g) →2COX2​(g)+HX2​O(ℓ);ΔH=−1310kJ The heat of formation of acetylene is

-1802 kJ

+1802 kJ

+237 kJ

-800 kJ

Q. Given:

$2 C (s) + 2 O X_{2} (g) 2 CO X_{2} (g); ΔH = - 787 kJ$

$H X_{2} (g) + \frac{1}{2} O X_{2} (g) H X_{2} O (ℓ); ΔH = - 286 kJ$

$C X_{2} H X_{2} (g) + 2 \frac{1}{2} O X_{2} (g) \to 2 CO X_{2} (g) + H X_{2} O (ℓ); ΔH = - 1310 kJ$

The heat of formation of acetylene is