An aqueous solution of glucose boils at `100.01^(@)C`.The molal elevation constant for water is `0.5 kmol^(-1)kg`. The number of molecules of glucose in the solution containing `100g` of water is

Options

A. `1.2 xx 10^(21)`
B. `2.0 xx 10^(22)`
C. `3.0 xx 10^(23)`
D. `6.0 xx 10^(11)`

Answer

A

Explanation

`Delta T_(b) = 0.01^(@) , omega_(A) = 100 g , K_(b) = 0.50 , M_(B) = 342`
`Delta T_(b)= (k_(b) xx 1000 xx w_(B))/(w_(A) xx M_(B))`
or `" " w_(B) = (Delta T_(b) xx w_(A) xx M_(B))/(k_(B) xx 1000)`
` = (0.01 xx 100 xx 342)/(0.50 xx 1000) = 0.684 g`
No. of molecules `= (0.684)/(342) xx 6.023 xx 10^(23)`
` = 1.2 xx 10^(21)`