Standard heat of formation of  Hydrazine_(l), hydrogen peroxide_(l) and water_(l) are -50.4, -193.2 and -242.7 kJ mol^-1  respectively at 298 K. Under standard states of the following reaction the heat of  reaction is –x what is the x value?

$(\Delta H_f^0{N}_2=0)$

${\mathrm{N}}_2\underset{\left(\mathrm{l}\right)}{{\mathrm{H}}_4}+2\underset{\left(\mathrm{l}\right)}{{\mathrm{H}}_2{\mathrm{O}}_2}\to \underset{\left(\mathrm{g}\right)}{{\mathrm{N}}_2}+4\underset{\left(\mathrm{l}\right)}{{\mathrm{H}}_2\mathrm{O}}$