The molality of 3M solution os mehtanol if the density of the solution is `0.9g cm^(-3)`, is
The molality of 3M solution os mehtanol if the density of the solution is `0.9g cm^(-3)`, is
A. 3.73
B. `3.0`
C. 3.33
D. 3.1
4 views
1 Answers
Correct Answer - a
`"Volume of the solution="1 L or 1000 cm^(3)`
`"Mass of the solution "=vxxd `
`= (1000cm(3)) xx (0.9 g cm^(3))=900 g`
`"Mass of methanol"(CH_(3)OH)=(3 molxx32 "g mol"^(-1))=96 g`
`"Mass of solvent" =(900-96g)=804 g=0.804 kg `
`"Molality of solution"=("No. of moles of methanol")/("Mass of solvent in kg")`
`(3mol)/(0.804kg)=0.373"mol kg"^(-1)`
=.373 molal
4 views
Answered