2Al+6HCl->2AlCl3+3H20
0,02...0,06..0,02
nAl=0,54/27=0,02mol
nHCl=0,07mol
=>hcl dư
AlCl3+3naoh->al(oh)3+3nacl
0,02....0,06.......0,02.......0,06
nNaOh bđ=0,075mol=>nnaoh dư
nnaoh dư=0,075-0,06=0,015mol
Naoh+al(oh)3->naalo2+2h20
0,015....0,015....0,015
nhcl dư=0,07-0,06=0,01mol...