Question

Insulin `(C_(2)H_(10)O_(5))_(n)` is dissolved in a suitable solvent and the osmotic pressure `(pi)` of solutions of various concentrations `(g//cm^(3))C` is measured at `20^(@)C`. The slope of a plot of `pi` against `C` is found to be `4.65 xx 10^(-3)`. The molecular weight of insulin is:
A. `4.8xx10^(5)`
B. `9xx10^(5)`
C. `3xx10^(5)`
D. `5.17xx10^(6)`

Answer 1

Correct Answer - D
`piV=(w_(B))/(m_(B))xxRT`
`pi=(w_(B)/(V))(RT)/(m_(B))`
`pi=cxx(RT)/(m_(B))xx1000`…..(i)
where C = concentrated in g/cc,
Comparing eqs.(i)and(ii),…(iii)
Slope `=(RT)/(m_(R))xx1000`
`m_(B)=(RT)/(Slope)xx1000`
`(0.0821xx293xx1000)/(4.65xx10^(-3))=5.17xx10^(6)J`