`#AkaShi`
`a)`
PTHH:
`3H_2SO_4 +2Al -> Al_2(SO_4)_3 + 3H_2↑`
`b)`
`→n_{Al}=(4,05)/27=0,15 (mol)`
`→n_{Al_2(SO_4)_3}=1/2xxn_{Al}=0,15xx1/2=0,075 (mol)`
`→m_{Al_2(SO_4)_3}=0,075xx342=25,65 (g)`
`c)`
`→n_{H_2SO_4}=0,15xx3/2=0,225 (mol)`
`→m_{H_2SO_4}=0,225xx98=22,05 (g)`
`→m_{dd\ H_2SO_4}=22,05:14,7%=150 (g)`