Assuming that the reaction proceeds to completion, then 137 mg of 4 -nitrotoluene will produce $\_\_\_\_$ mg of $B$.
(Given molar mass in $\mathrm{g} \mathrm{mol}^{-1} \mathrm{H}: 1, \mathrm{C}: 12, \mathrm{~N}: 14, \mathrm{O}: 16, \mathrm{Br}: 80$ )
