`a)`

`2Al+6HCl->2AlCl_3+3H_2`

`n_{Al}={0,54}/{27}=0,02(mol)`

`n_{H_2}=3/{2}n_{Al}=0,03(mol)`

`V_{H_2}=0,03.22,4=0,672(l)`

`b)`

`n_{HCl}=2n_{H_2}=0,06(mol)`

`C%_{HCl}={0,06.36,5}/{100}.100%=2,19%`

Bảo toàn electron:

     `2n_{Cu}=3n_{NO}+8n_{N_2O}`

`->n_{Cu}={3.0,05+8.0,1}/2=0,475(mol)`

`m_{Cu}=0,475.64=30,4(g)`

`CT:CH_4`

`n_{CH_4}={44,8}/{22,4}=2(mol)`

`m_{CH_4}=2.16=32(g)`