Question

0.7g of `(NH_(4))_(2)SO_(4)` sample was boiled with 100mL of 0.2 N NaOH solution was diluted to 250 ml. 25mL of this solution was neutralised using 10mL of a 0.1 N `H_(2)SO_(4)` solution. The percentage purity of the `(NH_(4))_(2)SO_(4)`sample is :
A. 94.3
B. 50.8
C. 47.4
D. 79.8

Answer 1

Correct Answer - A
m.eq of `(NH_(4))_(2)SO_(4)+` m.eq of `H_(2)SO_(4)`=m.eq of NaOH
`("m.molea"xx2)++(0.1xx10xx(250)/(25))=0.2xx100`
`:. " m.mole of " (NH_(4))_(2)SO_(4)=5`
wt. of `(NH_(4))_(2)SO_(4)=(5)/(1000)xx132=0.66 g`
`:. " % of " (NH_(4))_(2)SO_(4)=(0.66)/(0.7)xx100=94.28% ~~94.3%`