1.

The measured freezing point depression for a 0.1 m aqueous CH_(3)COOH solution is 0.19^(@)C. The acid dissociation constant K_(a) at this concentration will be (Given K_(f), the moala cryoscopic constant = 1.86 K Kg mol^(-1))

Answer»

`4.76xx10^(-5)`
`4XX10^(-5)`
`8xx10^(-5)`
`2xx10^(-5)`

Solution :`Delta T_(f)=ixxk_(f)xxm`
`i=(0.19)/(1.89xx0.1)=1.02`
`alpha =(i-1)/(n-1)=(0.02)/(1)=2xx10^(-2)`
`k_(a)=c alpha^(2)=1XX10^(-1)xx(2xx10^(-2))^(2)=4xx10^(-5)`


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