Two samples of `HCl` of `1.0 M` and `0.25 M` are mixed. Find volumes of these samples taken in order to prepare `0.75 M HCl` solution. Assume no water is added.
(I) `20 mL, 10 mL` (II) `100 mL, 50 mL`k
(III) `40 mL, 20 mL` (IV) `50 mL, 25 mL`

Options

A. 20 ml, 10 ml
B. 100 ml, 50 ml
C. 40 ml, 20 ml
D. 50 ml, 25ml

Answer

A,B,C,D

Explanation

Final molarity =`(V_1xx1+V_2xx0.25)/((V_1+V_2))`
`0.75(V_1+V_2)=V_1+V_2xx0.25`
`0.75 V_1+0.75 V_2=V_1+V_2xx0.25`
`0.5 V_2=0.25V_1`
`V_1/V_2=2`