Question

Using the data provided, calculate the multiple bond energy (kJ mol^-1) of a C=C bond in C₂ H₂ .That energy is (take the bond energy of a C – H bond as 350 kJ mol^-1)

2C(s) +H₂(g) C₂H₂(g); ΔH = 225kJ mol^-1

2C (s)→2C (g);  ΔH = 1410kJ mol^-1

H₂(g) →2H(g); ΔH= 330 kJ mol^-1

(A) 1165 

(B) 837 

(C) 865 

(D) 815

Answer 1

Correct option (D) 815    

Explanation:

∴ ∆H = +1410 + 330 – (350×2)– ε_C=C= +225 

∴ ε_C=C = 1740 – 700 – 225 = +815 KJ/mol.