1.

Insulin (C_(2)H_(10)O_(5))_(n) is dissolved in a suitable solvent and the osmotic pressure (pi) of solutions of various concentrations (C) is measured at 20^(@)C. The slope of the plot of pi (atm) versus C (in g//cm^(3)) is found to be 4.65xx10^(-3). The molecular weight of insulin is

Answer»

`3.17xx10^(6)`
`4.17xx10^(6)`
`5.17xx10^(6)`
`6.17xx10^(6)`

Solution :`pi=C'RT`. HENCE CONCENTRATION C' is in `"MOL L"^(-1)` To convert `"g cm"^(-3)` into `"mol L"^(-1)`, wehave
Thus, C' in the formula should be replaced by this factor, i.e.,
`pi=(Cxx1000)/(M_(2))RT=(1000RT)/(M_(2))C`
Thus, a plot of `pi` VS C will be linear with SLOPE
`=(1000RT)/(M_(2))=4.65xx10^(-3)"(Given)"`
`therefore (1000xx0.0821xx293)/(M_(2))=4.65xx10^(-3)`
`"or"M_(2)=5.17xx10^(6)`


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