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?
Derive the relation between the elevation of boiling point and molar mass of solute.
Account for the following :
H2S has lower boiling point than H2O.
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
Which has the lowest boiling point at 1 atm pressure?
People add sodium chloride to water while boiling eggs. This is to ____________.
Which of the following has the lowest boiling point?
Explain why on addition of 1 mol of NaCl to 1 litre of water, the boiling point of water increases, while addition of 1 mol of methyl alcohol to one litre of water decreases its boiling point.
Calculate the molal elevation constant for water given that 0.2 molal solution of non-volatile and non-electrolyte solute increases the boiling point of water by 0.104 K.
Boiling point of a 2% aqueous solution of a non-volatile solute A is equal to the boiling point of 8% aqueous solution of a non-volatile solute B. The relation between molecular weights of A and B is ______.
If the molality of a dilute solution is doubled, the value of the molal elevation constant (Kb) will be ______.
Calculate the boiling point elevation for a solution prepared by adding 10 g of MgCl2 to 200 g of water, assuming MgCl2 is completely dissociated.
(Kb for Water = 0.512 K kg mol−1, Molar mass MgCl2 = 95 g mol−1)
Which of the following aqueous solutions will exhibit the highest boiling point?
