a, \(n_{hhA}=\dfrac{56}{22,4}=2,5\left(mol\right)\)
b, \(\dfrac{n_{N_2}}{n_{H_2}}=\dfrac{1}{4}\Leftrightarrow\dfrac{n_{N_2}}{1}=\dfrac{n_{H_2}}{4}=\dfrac{n_{N_2}+n_{H_2}}{1+4}=\dfrac{2,5}{5}=0,5\)
\(\Rightarrow n_{N_2}=0,5.1=0,5\left(môl\right);n_{H_2}=2,5-0,5=2\left(mol\right)\)