Advertisements
Advertisements
प्रश्न
A solution containing 3 g of solute A (M = 60 g/mol) in 1 L solution is isotonic with a solution containing 8.55 g of solute B in 500 mL solution. What is the molar mass of B?
उत्तर
Given: Mass of solute A = (W2)A = 3 g
Volume = VA = 1 L
Molar mass of solute A = (M2)A = 60 g mol−1
Mass of solute B = (W2)B = 8.55 g
Volume = VB = 500 mL = 0.5 L
To find: Molar mass of solute B = (M2)B
Formula: π = `("W"_2"RT")/("M"_2"V")`
Calculation: For solution containing 3 g of solute A,
`pi_"A" = (("W"_2)_"A""RT")/(("M"_2)_"A" "V"_"A")` .....(i)
For solution containing 8.55 g of solute B,
`pi_"B" = (("W"_2)_"B""RT")/(("M"_2)_"B" "V"_"B")` .....(ii)
Since both the solutions are isotonic, πA = πB
∴ `(("W"_2)_"A""RT")/(("M"_2)_"A" "V"_"A") = (("W"_2)_"B""RT")/(("M"_2)_"B" "V"_"B")`
∴ `("M"_2)_"B" = (("W"_2)_"B" xx ("M"_2)_"A" xx "V"_"A")/(("W"_2)_"A" xx "V"_"B")`
`= (8.55 xx 60 xx 1)/(3 xx 0.5)` = 342 g mol-1
The molar mass of solute B is 342 g mol−1
संबंधित प्रश्न
Define ebullioscopic constant. Write its unit.
0·70g of an organic compound, when dissolved in 32g of acetone, produces an elevation of 0·25°C in the boiling point. Calculate the molecular mass of the organic compound (Kb for acetone = 1·72 K kg `mol^(-1)`).
The molecular weight of an organic compound is 58 g mol-1. What will be the boiling point of a solution containing 48 grams of the solute in 1200 grams of water?
[Kb for water = 0.513°C kg mole-1; Boiling point of water = 100°C]
Answer the following in one or two sentences.
Write the equation relating boiling point elevation to the concentration of the solution.
Answer the following in one or two sentences.
What is the effect on the boiling point of water if 1 mole of methyl alcohol is added to 1 dm3 of water? Why?
Answer the following.
While considering boiling point elevation and freezing point depression a solution concentration is expressed in molality and not in molarity. Why?
Explain with diagram the boiling point elevation in terms of vapour pressure lowering.
A solution of citric acid C6H8O7 in 50 g of acetic acid has a boiling point elevation of 1.76 K. If Kb for acetic acid is 3.07 K kg mol-1, what is the molality of solution?
Derive the expression for molar mass of solute in terms of boiling point elevation of solvent.
How will you determine the molar mass of non-volatile solute by elevation of boiling point?
The vapour pressure of water is 16.8 mm Hg at a certain temperature. If the vapour pressure of the solution is 16. 78 mm, find the molality of the solution.
As temperature increases ______.
