If air contains `71%N_(2)` by volume, the number of atoms of nitrogen per litre of air at STP is.

Options

A. `3.8 xx 10 ^(23)`
B. `0.38 xx 10 ^(23)`
C. `38 xx 10 ^(23)`
D. `0. 38 xx 10 ^(21)`

Answer

B

Explanation

Volume of `N_(2)` per litre of air`= 0. 71` litre
No. of .N. atoms per litre `= (0.71)/(22.4) xx 6. 02 xx 10 ^(23) xx 2 = 0. 38 xx 10 ^(23)`