109% labelled oleum has x mole of `H_(2)SO_(4)` and y mole of `SO_3` respectively. What is the value of (x+y)/(x-y)

Options

A. `8.81`
B. `9.91`
C. `10.6`
D. `11.6`

Answer

B

Explanation

109% oleum means it has `9 g H_(2)O` which reacts with fre `SO_3` to give `H_(2)SO_(4)`
According to stoichimetry `SO_(3)+H_(2)O rarr H_(2)SO_(4)`
Mass of `SO_3` which will react with `9 gH_(2)O=(80xx9)/(18)=40 g`
Let 100 g sample of 109% labelled oleum contain `40 g SO_(3)` and `60g H_(2)SO_(4)`
Mole of `H_(2)SO_(4)=(60)/(98)= 0.6122+x" "" moles of "SO_(3)=(40)/(80)=0.5=y`
`x+y=1.1122" " x-y =0.1122`
`(x+y)/(x-y) =(1.1122)/(0.1122)=9.91`