A) MO + 2HCl => MCl2 + H2O
M+16g...........................M+71g
0,8g................................1,9g
1,9M+30,4=0,8M+56,8 => 1,1M=26,4 => M=24
Metalul corespunzator => Mg , MMg=24g/mol
B) C=md/ms*100=>md=C*ms/100=20*219/100=43,8g HCl
M2O3 + 6HCl => 2MCl3 + 3H2O
2M+48g.......................6*36,5g
32g...............................43,8g
87,6M+2102,4=7008 => M=56
Oxidul este Fe2O3