Advertisements
Advertisements
प्रश्न
Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C? Molal elevation constant for water is 0.52 K kg mol−1.
Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C?
Advertisements
उत्तर
Here, elevation of boiling point (ΔTb) = (100 + 273) − (99.63 + 273)
= 0.37 K
Mass of water (w1) = 500 g
Molar mass of sucrose (C12H22O11), M2 = 11 × 12 + 22 × 1 + 11 × 16
= 342 g mol−1
Molal elevation constant (Kb) = 0.52 K kg mol−1
We know that,
ΔTb = `(K_b xx 1000 xx w_2)/(M_2 xx w_1)`
⇒ w2 = `(Delta T_b xx M_2 xx w_1)/(K_b xx 1000)`
= `(0.37 xx 342 xx 500)/(0.52 xx 1000)`
= 121.67 g (approximately)
= 122 g
Hence, 122 g of sucrose is to be added.
APPEARS IN
संबंधित प्रश्न
8 g of glucose, C6H12O6 (Molar Mass = 180 g mol−1) is dissolved in 1 kg of water in a sauce pan. At what temperature will this solution boil?
(Kb for water = 0.52 K kg mol−1, boiling point of pure water = 373.15 K)
Calculate the boiling point of solution when 4g of MgSO4 (M= 120 g mol-1) was dissolved in 100g of water, assuming MgSO4 undergoes complete ionization. (Kb for water = 0.52 K kgmol-1)
Out of 1 M glucose and 2 M glucose, which one has a higher boiling point and why?
Why is elevation of boiling point a colligative property?
Define the following term:
Colligative properties
Derive the relation between the elevation of boiling point and molar mass of solute.
Arrange the following increasing order of their boiling point:
CH3CH2OH, CH3CHO, CH3–O–CH3
Arrange the following in increasing order of boiling points:
(CH3)3 N, C2 H5 OH, C2 H5 NH2
0.450 g of urea (mol. wt. 60) in 22.5 g of water show 0.170°C of elevation in boiling point. The molal elevation constant of water is:
People add sodium chloride to water while boiling eggs. This is to ____________.
The molal elevation constant depends upon ____________.
Which of the following aqueous solutions should have the highest boiling point?
Which of the following has the lowest boiling point?
Why is it not possible to obtain pure ethanol by fractional distillation? What general name is given to binary mixtures which show deviation from Raoult’s law and whose components cannot be separated by fractional distillation. How many types of such mixtures are there?
The boiling point to a solution containing 50 gm of a non-volatile solute in 1 kg of solvent is 0.5° higher than that of pure solvent. Determine the molecular mass of the solute (give molecular mass of solvent) = 78 g mol–1 and kb for solvent = 2.53 km–1)
Molal elevation of boiling point constant is the elevation of boiling point produced by ______
Assertion (A): Elevation in boiling point is a colligative property.
Reason (R): The lowering of vapour pressure of solution causes elevation in boiling point.
Which of the following aqueous solution will have the highest boiling point?
