2Mg + O2----> 2MgO
0.045--0.0225--0.045
Ta có: no2=(19.92-19.2)/32=0.0225(mol) suy ra Mg dư
nMg dư = 19.2/24-0.0225*2=0.755 (mol)
MgO + 2HCl---> MgCl2+H2O (1)
0.045 0.045
Mg + 2HCl ----> MgCl2 + H2 (2)
0.0755 0.0755
=) V=(nH2(1)+nH2(2))22.4=(0.045+0.0755)22.4=17.92(l)