a)

2M+2nHCl→2MCln+nH22M+2nHCl→2MCln+nH2

nHCl=0,15.2=0,3(mol)nHCl=0,15.2=0,3(mol)

→nMCln=0,3.22n=0,3n(mol)→nMCln=0,3.22n=0,3n(mol)

MMCln=14,25:0,3n=47,5nMMCln=14,25:0,3n=47,5n

Ta có

MM+35,5=47,5n→MM=12nMM+35,5=47,5n→MM=12n

n=2 thì MM=24

→→ M là Magie(Mg)

Mg+2HCl→MgCl2+H2Mg+2HCl→MgCl2+H2

VH2=0,15.22,4=3,36(l)VH2=0,15.22,4=3,36(l)

CMMgCl2=0,150,15=1M