Thermodynamics

If 2 moles of \(\mathrm{C}_6 \mathrm{H}_6(\mathrm{~g})\) are completely burnt \(4100 \mathrm{~kJ}\) of heat is liberated. If \(\Delta H^{\circ}\) for \(\mathrm{CO}_2(\mathrm{~g})\) and \(\mathrm{H}_2 \mathrm{O}(l)\) are \(-410\) and \(-285 \mathrm{~kJ}\) per mole respectively then the heat of formation of \(\mathrm{C}_2 \mathrm{H}_6(g)\) is