In which ratio of volumes 0.4 M HCl and 0.9 M HCl are to be mixed such that the concentration of the resultant solution becomes 0.7 M ?

Options

A. `4:9`
B. `2:3`
C. `3:2`
D. `1:1`

Answer

B

Explanation

`0.4 xx 6+0.9 (1000-y)=0.7 xx 1000`
`0.4 y +900-0.9 y =700`
`0.5 y =700 -900= -200`
`0.5 y=200` or `y=400`
The ratio of volumes of 0.4 M HCl and 0.9 M HCl to be mixed to get 0.7 M concentration of the solution is `400 : 600` i.e., `2:3`