An aromatic compound contains 69.4% carbon and 5.8% hydrogen. A sample of 0.303g of this compound was analysed for nitrogen by Kjeldahl's method. The ammonia evolved was absorbed in 50 ml of 0.05 M sulphuric acid. The excess of acid required 25 ml of 0.1 M sodium hydroxide for neutralization. Determine the molecular formula of the compound if its molecular weight is 121. Draw twopossible structures for this compound.

An aromatic compound contains 69.4% carbon and 5.8% hydrogen. A sample

1.	An aromatic compound contains 69.4% carbon and 5.8% hydrogen. A sample of 0.303g of this compound was analysed for nitrogen by Kjeldahl's method. The ammonia evolved was absorbed in 50 ml of 0.05 M sulphuric acid. The excess of acid required 25 ml of 0.1 M sodium hydroxide for neutralization. Determine the molecular formula of the compound if its molecular weight is 121. Draw twopossible structures for this compound.
Answer» Answer :Calculation of `%` NITROGEN `50ml "of" % nitrogen (`because` Normality of `H_(2)SO_(4))=2xx` molarity) EXCESS of acid requires 25 ml of `0.1M` or `0.1 N NaOH` (`because` Normality of NaOH=molarity of NaOH) 25 ml of 0.1N NaOH-=25 ml of `0.1 N H_(2)SO_(4)` `therefore` VOL. of `0.1 NH_(2)SO_(4)` used for the neutralisation of `NH_(3)=50-25=25ml` NOw we know that, `%` of nitrogen `=(1.4xx"Normaility of acid"xx"Voll. of acid")rarr` `=(1.4xx0.1xx25)/(0.303)=11.55%`; Hence `%` of oxygen `=100-(69.4+5.8+11.55)=13.25`