Question

(a) Differentiate between molarity and molality in a solution. What is the effect of temperature change on molarity and molality in a solution? .
(b) What would be the molar mass of a compound if 6.21 g of it dissolved in 24.0g of chloroform from a solution tharhas a boiling point of `68.04^@C`. The boiling point of pure chloroform is `61.7^@C` and the boiling point elevation constant, `K_b` for chloroform is `3.63^@C//m`.

Answer 1

(a) Sec Q. (13) 2009,set -I (DB)
(b) Boiling point of solution `=68.7^@C`.
Boiling point of chloroform `=617^@C`
`K_b=3.63^@C//m`
`W_2=6.21g`
`W_1=24.0g`
`DeltaT_b =T_b-T_b^@=68.04-61.7=6.34^@C`
`M=(K_bxxW_2xx1000)/(W_1xxDeltaT_b)=(3.63xx6.21xx1000)/(24.0xx6.34)`
`=22542.3/152.16=148.15//g//mol`.