Răspuns:
masa de Mg= 20,4x47/100g= 9,58g
moliMg= m/M= 9,58/24mol=0,4mol
masa de Al= 20,4-9,58=>10,8g
moli Al= m/M=10,8/27mol= 0,4mol
moli total HCl
1mol......2mol
Mg + 2HCl---> MgCl2 + H2
0,4mol.......x=niu= 0,8mol
1mol.....3mol
Al + 3HCl ------> AlCl3 + 3/2H2
0,4mol....x=niu=1,2mol
niu,total HCl= 2mol
masa HCl= niuxM= 2X36,5g=73g
c= mdx100/ms---> ms= 73x100/35,38g=206g
v,s= m/ro= 206/1,1 ml=187,3 ml
Explicație: