150 ml of a solution containing 5 millimoles of A (special gravity =1.2) is mixed 250 ml of another solution containing 10 millimoles of A (special gravity =1.4). If one mixing the density of the solution becomes `5.3/4.5 ` gm/ml then what will be molarity of A in the total final solution .

Options

A. `1/30M `
B. `3/80 M`
C. `1/20`
D. `4/25`

Answer

A

Explanation

`d_(1)v_(1)+d_(2)v_(2)=d_(3)v_(3)`
`150xx1.2+250xx1.4=4.5/5.3xxv_(3)`
`180+350=4.5/5.3 v_(3) rArr 450 ml`
`M=15/450 =1/30 M`