The following are the heats of reactions-
i)ΔH^OofHO(l)=–68.3Kcalmol–1
ii)ΔH^O comb ofC₂H₄ =–337.2Kcalmol–1
iii) ΔH^O comb ofC₂H₄ =–363.7Kcalmol–1Then heat change for the reaction
C2H2+H2→C2H4is-</span

1. –716.1Kcal    
2. +337.2Kcal    
3. –41.8Kcal    
4. –579.5Kcal