Trong A :
\(n_{CO_2}=n_X=a\left(mol\right)\)
Trong B:
\(n_{N_2}=2b\left(mol\right),n_{CO_2}=3b\left(mol\right)\)
\(n_A=2a=0.1\left(mol\right)\Rightarrow a=0.05\)
\(n_B=5b=0.05\left(mol\right)\Rightarrow b=0.01\)
\(m=0.05\cdot44+0.05\cdot X+0.02\cdot28+0.03\cdot44=4.18\left(g\right)\)
\(\Rightarrow X=2\)
\(X:H_2\)