A gaseous mixture contains 1 gram of Hydrogen and 8.5 grams of ammonia. Ratio of atoms of Hydrogen to Ammonia will be

$W_{H_2}:W_{N{H}_3}=1:8.5$
$n_{H_2}:n_{N{H}_3}=\frac{1}{2}:\frac{8.5}{17}$
$n_{H_2}:n_{N{H}_3}=1:1$
           Atomicity of  $H_2$ = 2;  Atomicity of   $N{H}_3$= 4
Ratio of atoms of Hydrogen to Ammonia = 1(2) : 1(4)
                                                                                   = 1 : 2