Răspuns:
p= m,purx100/m,impur---> 90/100= m,p/100-----> m,pur=90gNaCl
a
1molCa.........1molH2
5mol..................x x= 5mol H2
1mol Cl2...........1molH2
4mol Cl2...........x
x= 4mol H2-----> exces 2 mol H2
Explicație: