Question

How much would the boiling point of water increase if 4 mol of sugar were added to 1 kg of water (Kb = 0.51°C/(mol/kg) for water and i = 1 for sugar)?

Answer 1

Answer:

2.04°C

Explanation:

Answer 2

Answer : The boiling point of water increases, $2.04^oC$

Solution : Given,

Moles of solute (sugar) = 4 moles

Mass of solvent (water) = 1 Kg

$K_b=0.51Kg^oC/mole$

i = 1 for sugar

Formula used :

$\Delta T_b=i\times K_b\times m\\\Delta T_b=i\times K_b\times \frac{n_{solute}}{w_{solvent}}$

Where,

$\Delta T_b$ = elevation in boiling point

$K_b$ = elevation constant

m = molality

$n_{solute}$ = moles of solute (sugar)

$w_{solvent}$ = mass of solvent (water)

i = van't Hoff factor

Now put all the given values in this formula, we get the elevation in boiling point of water.

$\Delta T_b=(1)\times (0.51Kg^oC/mole)\times \frac{4moles}{1Kg}=2.046^oC$

Therefore, the elevation in boiling point of water is $2.04^oC$