Why is freezing point depression of 0.1 M sodium chloride solution nearly twice that of 0.1 M glucose solution?

Answer:

0.1M NaCl and0.1M glucose solution means that 0.1 moles of solute dissolve in 1L of solvent.

weight of solvent in both solution is same .
Dpression in freezing point can br calculated as :

Tf = Kf×wB×1000wA × MB

Where 
Kf = molal depression constant
wB = weight of solute
wA= weight of solvent
MB = molar mass of the solute

mass of NaCl = 58.69g/mol
mass of glucose = 180g/mol

The depression in freezingpoint is inversly proprotional to molar mass of solute thus more is molar mass of solute lesser is the depression in freezing point .
Thus it can explain that the NaCl wil be more than the glucose.

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Urea forms an ideal solution in water. Determine the vapour pressure of an aqueous solution containing 10% by mass of urea at 400C. (Vapour pressure of water at 400C = 55.3 mm of Hg)

Answer:

by using formula .

p° -pp° = xurea

let the mass of solution be 100g
therefore mass of urea = 10g
molecular mass of urea = 60 g

xurea = 10/60 = 1/6

molecular mass of water = 18 g
 xwater = 90/18 = 5

mole fraction of urea =xurea =1/61/6+5 = 1/631/6xurea =1/31using above formula 55.3-p55.3 =13155.3- p = 55.33155.3- 55.331 = p55.31-131 =pp= 55.3 ×3031 =53.52mm Hg

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Give reasons for the following:
Copper is conducting as such while copper sulphate is conducting only in molten state or in aqueous solution.


Answer:

Copper sulphate conduct electricity only in molten state or in aqueous phase because on dissolving or melting it. copper sulphate dissociate in copper ion and sulphate ion and became free to move.
As they are freeto move in molten and aqueous phase the charge particle conduct electricity.

CuSO4    Cu2+  + SO42-

In solid and any other ionic form the ions held in a lattice and unable to move so they are not conduct electricity. 

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A 6.90 M solution of KOH in water contains 30% by mass of KOH. Calculate the density of the KOH solution. (Molar mass of KOH = 56 g mol–1

Answer;

Let the mass of solution =100g

xKOH = 30/56

volumeof solution = mass of solutiondensity of solution

= 100gd g/cm3 = 100dcm×11000 =110dLMolarity  = number of moles of solute volume of solution6.90 = 30/561/10d 6.90 = 3056×10d1d =1.288g/cm

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Give reasons for the following:
When 30 ml of ethyl alcohol and 30 ml of water are mixed, the volume of resulting solution is more than 60 ml.

Answer:

When 30 ml of ethyl alcohol and 30 ml of water are mixed, the volume of resulting solution is more than 60ml.
It is because ethyl alchol and water do not form an ideal solution intermolecular forces of attraction are weak so the molecule will become farapart from each other hence volume will increase.

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