In a Duma's method `0.3g` of an organic compound gave `50ml` of nitrogen collected at `27^(@)C` and `715mm` pressure . The percentage of N is (aqueous tension at `27^(@)C=15mm`) :

Options

A. `19.46%`
B. `21.46%`
C. `17.46%`
D. `36.64%`

Answer

C

Explanation

Vapour pressure of gas `=715-15`
`=700mm`
To calculate the volume of `N_(2)` at S.T.P
`{:(V_(1)=50mL,V_(2)=?),(p_(1)=700mm,p_(2)760mm),(T_(1)=300K,T_(2)=273K):}`
Applying `(p_(1)V_(1))/(T_(1))=(p_(2)V_(2))/(T_(2))`
or `V_(2)=(p_(1)V_(1)T_(2))/(p_(2)T_(1))`
`:.V_(2)=(700xx50xx273)/(760xx300)`
`=41.9mL`
`22400mL` of nitrogen at S.T.P.weigh `=28g`
`41.9mL` of nitrogen at S.T.P.weigh
`=(28xx41.9)/(22400)`
`=0.0524g`
Percentage of nitrogen
`=(0.0524)/(0.3)xx100=17.46%`