Freezing point of a 4% aqueous solution of X is equal to freezing point of 12% aqueous is reaction of Y .if molecular weight of X is A then molecular weight of Y is :

Options

A. 2A
B. 3A
C. A
D. 4A

Answer

B

Explanation

For solutions having same freezing point , their molalities and shoul be same .
`m(X) = m(Y)`
`( 4 xx 1000)/(96 xx M(X)) = (12 xx 100)/(88 xx M(Y))`
`M(Y) = (12 xx 96 xxA)/(4 xx 88) = 3.27 A or 3A`