The degree of dissociation of Ca(NO_(3))_(2) in a dilute aqueous solution containing 7g of the salt per 100g of water at 100^(@)C is 70 per cent. If the vapour pressure of water at 100^(@)C is 760mm, calculate the vapour pressure of the solution.

The degree of dissociation of Ca(NO_(3))_(2) in a dilute aqueous solut

1.	The degree of dissociation of Ca(NO_(3))_(2) in a dilute aqueous solution containing 7g of the salt per 100g of water at 100^(@)C is 70 per cent. If the vapour pressure of water at 100^(@)C is 760mm, calculate the vapour pressure of the solution.
Answer» Solution :`{:(1,,,,,,,,),(Ca(NO_(3))_(2),,to,,Ca^(2+),,+,,2NO_(3)^(-)),(1-x,,,,x,,,,2x):}` van.t Hoff factor `i=(1-x+x+2x)/(1)=(1+2x)/(1)=1+2xx0.7=2.4` Now, `i=("observed lowering of VAPOUR PRESSURE")/("normal lowering of vapour pressure")` `:.` obs. lowering of vap. PRESS. `=ixx` nor.lowering of vap.press. `p^(0)-p_(obs.)=ixx{(n)/(n+N).p^(0)}` `760-p_(obs)=2.4xx(7//164)/((7)/(164)+(100)/(18))xx760` `{{:(Ca(NO_(3))_(2)=164),(H_(2)O=18):}}` `=13.90` `:.p_(obs.)=760-13.90=746.10mm`