Advertisements
Advertisements
प्रश्न
An aqueous solution of 2% non-volatile solute exerts a pressure of 1.004 bar at the normal boiling point of the solvent. What is the molar mass of the solute?
Advertisements
उत्तर
Here, the vapor pressure of the solution at normal boiling point (ps) = 1.004 bar
Vapour pressure of pure water at normal boiling point (p°) = 1 atm = 1.013 bar
Let mass of solution = 100 g
Mass of solute (w2) = 2 g
Mass of solvent (water), (w1) = 100 − 2 = 98 g
Molar mass of solvent (water), (M1) = 18 g mol−1
According to Raoult’s law,
`(p^circ - p_s)/p^circ = n_2/(n_1 + n_2) = n_2/n_1`
= `(w_2//M_2)/(w_1//M_1) = w_2/M_2 xx M_1/w_1`
`=> (1.013 - 1.004)/1.013 = (2 xx 18)/(M_2 xx 98)`
`=> 0.009/1.013 = (2 xx 18)/(M_2 xx 98)`
`=> M_2 = (1.013 xx 2 xx 18)/(0.009 xx 98)`
= 41.35 g mol−1
Hence, the molar mass of the solute is 41.35 g mol−1.
संबंधित प्रश्न
In non-ideal solution, what type of deviation shows the formation of maximum boiling azeotropes?
Define azeotropes.
Why does a solution containing non-volatile solute have higher boiling point than the pure solvent ?
Vapour pressure of pure water at 298 K is 23.8 mm Hg. 50 g of urea (NH2CONH2) is dissolved in 850 g of water. Calculate the vapour pressure of water for this solution and its relative lowering.
The vapour pressure of water is 12.3 kPa at 300 K. Calculate vapour pressure of 1 molal solution of a non-volatile solute in it.
Calculate the mass of a non-volatile solute (molar mass 40 g mol−1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
What type of azeotrope is formed by positive deviation from Raoult’s law?
For the reaction :
\[\ce{2NO_{(g)} ⇌ N2_{(g)} + O2_{(g)}}\];
ΔH = -heat
Kc = 2.5 × 102 at 298K
What will happen to the concentration of N2 if :
(1) Temperature is decreased to 273 K.
(2) The pressure is reduced
Match the following:
| (i) | Colligative property | (a) | Polysaccharide |
| (ii) | Nicol prism | (b) | Osmotic pressure |
| (iii) | Activation energy | (c) | Aldol condensation |
| (iv) | Starch | (d) | Polarimeter |
| (v) | Acetaldehyde | (e) | Arrhenius equation |
Define Raoult’s law for the elevation of the boiling point of a solution.
What will be the vapour pressure of a solution containing 5 moles of sucrose (C12H22O11) in 1 kg of water, if the vapour pressure of pure water is 4.57 mm of Hg? [C = 12, H = 1, O = 16]
Minimum boiling azeotrope is formed by the solution which showed
An aqueous solution of hydrochloric acid:
The boiling point of an azeotropic mixture of water and ethanol is less than that of water and ethanol. The mixture shows ____________.
Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?
On the basis of information given below mark the correct option.
On adding acetone to methanol some of the hydrogen bonds between methanol molecules break.
Two liquids X and Y form an ideal solution. The mixture has a vapour pressure of 400 mm at 300 K when mixed in the molar ratio of 1 : 1 and a vapour pressure of 350 mm when mixed in the molar ratio of 1 : 2 at the same temperature. The vapour pressures of the two pure liquids X and Y respectively are ______.
The vapour pressure of pure liquid X and pure liquid Y at 25°C are 120 mm Hg and 160 mm Hg respectively. If equal moles of X and Y are mixed to form an ideal solution, calculate the vapour pressure of the solution.
