1.

The freezing point of water is depressed by 0.37^(@)C in a 0.01 molal NaCl solution. The freezing point of 0.02 molal solution of urea is depressed by

Answer»

`0.37^(@)C`
`0.74^(@)C`
`0.185^(@)C`
`0^(@)C`

Solution :The depression in FREEZING point is proportional to molal concentration of the SOLUTE i.e.
`Delta T_(f) prop m`
`Delta T_(f)=K_(f)mi` or `K_(f)=(Delta T_(f))/(ixxm)` = constant
so, `(Delta T_(f_(NaCl)))/(i_(NaCl)xxm_(NaCl))=(Delta T_(f_("UREA")))/(m_("Urea")xxi_("Urea"))` = constant
`(0.37)/(2xx0.01)=(Delta T_(f_("Urea")))/(0.02xx1)rArr Delta T_(f_("Urea"))=(0.37xx0.02)/(0.02)=0.37^(@)C`.


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