Moles of `K_(2)SO_(4)` to be dissolved in 12 moles of water of lower its vapour pressure by 10mm Hg at a temperature at which vapour pressure of pure water is 50mm Hg is

Options

A. 3 mol
B. 2 mol
C. 1 mol
D. 0.5 mol

Answer

C

Explanation

Lowering ofV.P.is colligative property
thus,`i_(K_(2)SO_(4))=1+(y-1)x=1+2x=3`
`:.` If `(cancel(O)p)/(P^(@))=(n_(1)i)/(n_(1)i+n_(2))`
`(10)/(50)=(3n_(1))/(3n_(1)+12)=(n_(1))/(n_(1)+4)n_(1)=1`