The required equation is
2C(s)+2H2(g)+O2(g)=CH3COOH(l);ΔH=?
This equation can be obtained by multiplying eq (ii) by 2 and also eq.(iii) by 2 and adding both and finally subtracting eq.(i)
[2C+2O2+2H2+O2−CH3COOH(l)−2O2→2CO2+2H2O−2CO2−2H2O]
ΔHCH3COOH=2×(−94.48)+2×(−68.4)−(−207.9)
=−188.96−136.8+207.9
=−325.76+207.9=−117.86 kcal