What volumes of 10N HCl and 2N HCl should you mix to obtain 4 litres of 5N HCl solution ?

Explanation

Assume V litres of 10N HCl is mixed with (4-V) litres of 2N HCl i.e., `V_1=V` and `V_2`=(4-V)
`therefore N_"Total"=(N_1V_1+N_2V_2)/V_"Total"`
`therefore N_"Total" xx V_"Total" =N_1V_1+N_2V_2`
`therefore N_"Total" xx V_"Total" =N_1V_1 +N_2V_2`
`5xx4=10xxV_1 + 2V_2`
`5xx4=10 xx V + 2(4-V)`
`therefore` V=1.5 Litres
i.e. `V_1` = 1.5 litres and `V_2`= 2.5 litres