Đáp án:
Giải thích các bước giải:
`a.`
`n_{HCl}=0,1.2=0,2(mol)`
`n_{Ba(OH)_2}=0,4.1=0,4(mol)`
`Ba(OH)_2+2HCl->BaCl_2+2H_2O`
`(0,4)/1<(0,2)/2=>Ba(OH)_2` dư
`n_{BaCl_2}=0,5n_{HCl}=0,1(mol)`
`m_{BaCl_2}=0,1.208=20,8(g)`
`b.`
`n_{Ba(OH)_2pư}=0,5n_{HCl}=0,1(mol)`
`n_{Ba(OH)_2dư}=0,4-0,1=0,3(mol)`
`V_{ddspư}=0,1+0,4=0,5(l)`
`C_{M_{Ba(OH)_2}}=(0,3)/(0,5)=0,6(M)`
`C_{M_{BaCl_2}}=(0,1)/(0,5)=0,2(M)`