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

Let the volume of `0.4" M HCI" " is"` `V_(1)` and that of `0.9" M HCI " " is"` `V_(1).`
We no that,
`{:(NV,=,N_(1)V_(1),+,N_(2)V_(2)),("(Mixture)",,("for " 0.4 MHCI),,("for " 0.9 M HCI)):}`
`0.7(V_(1)+V_(2))=0.4xxV_(1)+0.9xxV_(2)" [":'1MHCI=1NHCI]`
`0.7V_(1)+0.7V_(2)=0.4V_(1)+0.9V_(2)`
`0.3V_(1)=0.2V_(2)`
`(V_(1))/(V_(2))=(0.2)/(0.3)=(2)/(3)`