Given that, 2 C (s)+2 O 2(g) arrow 2 CO 2(g) ; Δ H=-787 kJ H 2(g)+(1/2) O 2(g) arrow H 2 O (l) ; Δ H=-286 kJ C 2 H 2(g)+(5/2) O 2(g) arrow 2 CO 2(g)+ H 2 O (l) ; Δ H=-1301 kJ Heat of formation of acetylene is

Question

Given that, 2 C (s)+2 O 2(g) arrow 2 CO 2(g) ; Δ H=-787 kJ H 2(g)+(1/2) O 2(g) arrow H 2 O (l) ; Δ H=-286 kJ C 2 H 2(g)+(5/2) O 2(g) arrow 2 CO 2(g)+ H 2 O (l) ; Δ H=-1301 kJ Heat of formation of acetylene is (A) -1802 kJ (B) +1802 kJ (C) -800 kJ (D) +228 kJ

Tardigrade Admin · Accepted Answer

Aim :2 C (s)+ H 2(g) arrow C 2 H 2(g) Operate (i) +( ii )-( iii ), we get Δ H=-787+(-286)-(-1301)=+228 kJ

Q. Given that,
$2 C_{(s)} + 2 O_{2 (g)} \to 2 C O_{2 (g)}; Δ H = - 787 k J$
$H_{2 (g)} + \frac{1}{2} O_{2 (g)} \to H_{2} O_{(l)}; Δ H = - 286 k J$
$C_{2} H_{2 (g)} + \frac{5}{2} O_{2 (g)} \to 2 C O_{2 (g)} + H_{2} O_{(l)}; Δ H = - 1301 k J$
Heat of formation of acetylene is

$- 1802 k J$

$+ 1802 k J$

$- 800 k J$

$+ 228 k J$

Aim : $2 C_{(s)} + H_{2 (g)} \to C_{2} H_{2 (g)}$

Operate (i) $+ (ii) - (iii),$ we get

$Δ H = - 787 + (- 286) - (- 1301) = + 228 k J$

Q. Given that, 2C(s)​+2O2(g)​→2CO2(g)​;ΔH=−787kJ H2(g)​+21​O2(g)​→H2​O(l)​;ΔH=−286kJ C2​H2(g)​+25​O2(g)​→2CO2(g)​+H2​O(l)​;ΔH=−1301kJ Heat of formation of acetylene is

−1802kJ

+1802kJ

−800kJ

+228kJ