Thermodynamics

At 25$^\circ$C and 1 atm pressure, the enthalpy of combustion of benzene (I) and acetylene (g) are $-$ 3268 kJ mol^$-$1 and $-$1300 kJ mol^$-$1, respectively. The change in enthalpy for the reaction 3 C₂H₂(g) $\to$ C₆H₆ (I), is :