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Depression in freezing point of 0.01 m aqueous acetic acid solution is found to be 0.0246 K. One molal urea solution freezes at -1.86^(@)C. Assuming molarity equal to molality, pH of acetic acid solution is

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SOLUTION :For a m urea solution, `DeltaT_(f)=K_(f)m` gives
`K_(f)=1.86^(@)C//m`
For acetic acid, `DeltaT_(f)=iK_(f)m`
`0.2046=ixx1.86xx0.01 or I = 1.1`
`{:(,CH_(3)COOH,hArr,CH_(3)COO^(-),+,H^(+)),("Initial","C mol L"^(-1),,,,),("After disso.",C-CALPHA,,Calpha,,Calpha","):}`
`"Total "=C+C alpha=C(1+alpha)`
`therefore""i=(C(1+alpha))/(C)=1+alpha or alpha=i-1=0.1`
`[H^(+)]=Calpha=(0.01)(0.1)=10^(-3M`
Hence, `pH=3`


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