You visited us 4 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Chemistry

Depression in Freezing Point

Calculate the...

Question

Calculate the density of glycol solution whose $2.976 L$ on addition to $5 L$ of water produce an antifreeze which protects automobile radiator down to $- 20^{o} C$ . . $K_{f}$ and $K_{B}$ for water are $1.86$ and $0.51 K$ $m o l^{- 1}$ kg respectively. Answer should be the nearest integer value.

Open in App

Solution

The depression in the freezing point $Δ T_{f} = 0 - (- 20) = 20^{o} C$
The molality of solution $m = \frac{Δ T_{f}}{K_{f}} = \frac{20}{1.86} = 10.75 m$
1 kg (or 1000 g) of water contains 10.75 moles of glycol.
5 litre (or 5 kg) of water will contain $5 \times 10.75 = 53.76$ moles of glycol. The molar mass of glycol is 62 g/mol. Mass of glycol $= 53.76 \times 62 = 3333.3 g$
Total mass of solution $= 3333.3 + 5000 = 8333.3 g$
Total volume $= 2976 + 5000 = 7976$
Density $= \frac{m a s s}{v o l u m e} = \frac{8333.3}{7976} = 1.12 g / m L$

Suggest Corrections

Similar questions

Q. Ethylene glycol,

C H_{2} O H \cdot C H_{2} O H

, the major component of permanent antifreeze, effectively depresses the freezing point of water in an automobile radiator. What minimum weight of ethylene glycol must be mixed in kg with 6 gallons of water to protect it from freezing at

- 24^{\circ} C . (1 gallon = 3.785 lit, K_{f} = 1.86)

Q. Ethylene glycol is used as an antifreeze in a cold climate. Mass of ethylene glycol which should be added to

4

kg of water to prevent it from freezing at

- 6^{o} C

will be :

(

K_{f}

for water =

1.86

K kg/mol and molar mass of ethylene glycol =

62

g mol

^{- 1}

)

What mass of ethylene glycol (M.W. = 62.1 g/mol) antifreeze must be added to 10.0 mL of water to produce a solution that freezes at -186 °C. Density of water is 1g / mL and K_f = l.86 °C/m.

Q. The freezing point of a solution containing 28.335

c m^{3}

of ethylene glycol in 50 g water is found to be

- 34^{\circ}

C. Assuming ideal behaviour, calculate the density of ethylene glycol.

K_{f}

for water 1.86 K kg

m o l^{- 1}

.___

Q. A solution of urea in water has a boiling point of

{100.18}^{\circ} C .

Calculate the freezing point of the same solution. Molal depression and elevation constants for water

K_{f}

and

K_{b}

are

{1.86}^{\circ} C k g m o l^{- 1}

and

{0.512}^{\circ} C k g m o l^{- 1}

respectively.

Join BYJU'S Learning Program

Calculate the density of glycol solution whose 2.976L on addition to 5L of water produce an antifreeze which protects automobile radiator down to −20oC. . Kf and KB for water are 1.86 and 0.51 K mol−1 kg respectively. Answer should be the nearest integer value.

Calculate the density of glycol solution whose $2.976 L$ on addition to $5 L$ of water produce an antifreeze which protects automobile radiator down to $- 20^{o} C$ . . $K_{f}$ and $K_{B}$ for water are $1.86$ and $0.51 K$ $m o l^{- 1}$ kg respectively. Answer should be the nearest integer value.