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
Why is elevation of boiling point a colligative property?
Define the following term:
Molal elevation constant (Kb)
Define the following term:
Colligative properties
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
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:
Exactly 1 g of urea dissolved in 75 g of water gives a solution that boils at 100.114°C at 760 torrs. The molecular weight of urea is 60.1. The boiling point elevation constant for water is:
Which has the lowest boiling point at 1 atm pressure?
Which of the following aqueous solutions should have the highest boiling point?
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.
Molal elevation of boiling point constant is the elevation of boiling point produced by ______
AB2 is 10% dissociated in water to A2+ and B−. The boiling point of a 10.0 molal aqueous solution of AB2 is ______°C. (Round off to the Nearest Integer).
[Given: Molal elevation constant of water Kb = 0.5 K kg mol−1 boiling point of pure water = 100°C]
Which of the following aqueous solution will have the highest boiling point?
Which of the following aqueous solutions will exhibit the highest boiling point?
