Question

2.0267 g of the nitrate of a univalent metal was heated with excess of previously ignited silica. A loss in weight of 1.08 g took place due to the total expulsion of the nitrate part of the salt as `N_2O_5`, calculate the percentage of `NO_3^(ɵ)` group in the salt analysed.

Answer 1

Loss in weight is due to expulsion of `N_2O_5`
Weight of `N_2O_5=1.09g`
`N_2O_5-=2NO_3^(ɵ)`
1 mol 2 mol
108 g 124 g
`therefore1.08g of N_2O_5-=(124xx1.08)/(108)-=1.24 g of NO_3^(ɵ)`
Weight of `NO_3^(ɵ)` in the salt `=1.24g`
`therefore%` of `NO_3^(ɵ)` in the salt`=(1.24xx100)/(2.0267)=61.2%`