`#AkaShi`
`Mg + 2HCl -> MgCl_2 + H_2↑`
`n_{Mg}=18/24=0,75 (mol)`
`⇒n_{HCl}=2n_{Mg}=2xx0,75=1,5 (mol)`
`⇒m_{HCl}=1,5xx36,5=54,75 (g)`
`⇒C%_{HCl}=(54,75)/250xx100%=21,9 %`
`n_{H_2}=n_{Mg}=0,75 (mol)`
`⇒V_{H_2}=0,75xx22,4=16,8 (l)`
b) `n_{MgCl_2}=n_{Mg}=0,75 (mol)`
`⇒m_{MgCl_2}=0,75xx95=71,25 (g)`
`m_{dd sau pư}=18+205-0,75.2=221,5 (g)`
`⇒C%_{MgCl_2}=(71,25)/(221,5)xx100%≈32,17%`
