Question

if ch4 (g)--c(g)+4H(g), delta H=400KJ & C2 h6--2c(g)+6H(g), delta H=1000kJ. the value of BEc-c will be:-​

Answer 1

if ch4 (g)--c(g)+4H(g), delta H=400KJ & C2 h6--2c(g)+6H(g), delta H=1000kJ. the value of BEc-c will be:-

answer : 200 KJ

explanation : CH4(g) ⇒C(g) + 4H(g) ; ∆H = 400KJ

so, bond energy of each C—H bond = 400/4 = 100KJ

again, C2H6 (g) ⇒2C(g) + 6H(g) ; ∆H' = 1000 KJ

so, 2 × Bond energy of C — C + 6 × bond energy of C — H = 1000 KJ

⇒2 × bond energy of C — C + 6 × 100 KJ = 1000KJ

⇒2 × bond energy of C — C = 400 KJ

⇒bond energy = 200 KJ