\(n_{HX}=\dfrac{1,568}{22,4}=0,07\left(mol\right)\\ X_2+H_2\rightarrow\left(tu\text{ỳ}.\text{Đ}K\right)2HX\\ n_{X_2}=\dfrac{0,07}{2}=0,035\left(mol\right)\\ M_{X_2}=\dfrac{2,485}{0,035}=71\left(\dfrac{g}{mol}\right)\\ \Rightarrow M_X=35,5\left(\dfrac{g}{mol}\right)\\ \Rightarrow X:Clo\left(Cl=35,5\right)\)