Question

The vapour pressured of pure water at 250

C is 23.62mm. What will be the

vapour pressure of a solution of 1.5gm of urea in 50gm of H2O​

Answer 1

it has given that, the vapor pressure of pure water at 250°C is 23.62 mm.

We have to find the pressure of solution of 1.5g of urea in 50g of water.

solution : we know, relative lowering of vapor pressure = mole fraction of solute

Mole fraction of solute (urea), x = no of moles of urea/(no of moles of urea + no of moles of water)

= (1.5/60)/(1.5/60 + 50/18)

≈ 0.009

Here P° = 23.62 mm , P = ?

Now (P° - P)/P° = x

⇒(23.62 - P)/23.62 = 0.009

⇒23.62 - p = 23.62 × 0.009

⇒23.62 - 23.62 × 0.009 = P

⇒23.62(1 - 0.009) = P

⇒23.62 × 0.991 = 23.47 = P

Therefore the pressure of solution is 23.47 mm

Answer 2

Answer:

23.47mm is answer.......