Question

1,3-Dinitrobenzene can be prepared by heating nitrobenzene with a mixture of fuming nitric acid and concentrated sulphuric acid. If the yield of the reaction is 55%, the mass of 1,3-dinitrobenzene produced from 12.30g of nitrobenzene is......?

Answer 1

hypothetical equation:-
C6H5NO2 + NO2 ---> C6H4(NO2)^2

Answer 2

form the above
123g of the nitro compound gives 168g of the dinitro compound
but as the yield is 55% it gives 168* 0.55 g

so 12.3 g of the nitro will give 168 * 0.55 * 12.3
-------------- g of the dinitrobenzene
123

Answer 3

How do we know that 168g of dijitrobenzene will be produced?