Question

20 gm sample containing Mg. is treated with excess of 2M HCl. As a result 11.2 litre of `H_(2)` gas at NTP was evolved. Find % purity of Mg in sample
A. 0.6
B. 0.3
C. 0.75
D. 0.72

Answer 1

`Mg+2HClrarrMgCl_(2)+H_(2)`
`n_(Mg)=n_(H_(2))=(11.2)/(22.4)=(1)/(2)`
`w_(Mg)=12gm`
`% "purity"=(12)/(20)xx100=60`