HSC Science (Electronics) १२ वीं कक्षा - Maharashtra State Board Important Questions for Chemistry

The vapour pressure of water at 20°C is 17 mm Hg. What is the vapour pressure of solution containing 2.8 g urea in 50 g of water?

A solution of citric acid C₆H₈O₇ in 50 g of acetic acid has a boiling point elevation of 1.76 K. If K_b for acetic acid is 3.07 K kg mol^-1, what is the molality of solution?

A mixture of benzene and toluene contains 30% by mass of toluene. At 30°C, vapour pressure of pure toluene is 36.7 mm Hg and that of pure benzene is 118.2 mm Hg. Assuming that the two liquids form ideal solutions, calculate the total pressure and partial pressure of each constituent above the solution at 30°C.

The Henry’s law constant of a gas is 6.7 × 10^–4 mol/(L bar). Its solubility when the partial pressure of the gas at 298 K is 0.65 bar is ______.

State Raoult’s law. 

The vapour pressures of pure liquids A and B are 0.600 bar and 0.933 bar respectively, at a certain temperature.
What is the mole fraction of liquid B in the solution when the total vapour pressure of their mixture is 0.8 bar?

For a very dilute solution, the osmotic pressure is given by π = n₂RT/V where V is the volume in L containing n₂ moles of nonvolatile solute. Establish the equation for molar mass of solute.

Give two points to explain why vapour pressure of solvent is lowered by dissolving nonvolatile solute into it.

Derive the expression for molar mass of solute in terms of boiling point elevation of solvent.

With the help of vapour pressure-temperature curves for solution and solvent, explain why boiling point of solvent is elevated when a nonvolatile solute is dissolved into it.

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?

Explain with vapour pressure-temperature curves that the freezing point of a solvent is lowered by dissolving a nonvolatile solute into it. Give reason for such lowering of freezing of solvent.

Henry's law constant for CH₃Br_(g) is 0.159 mol dm^–3 bar^–1 at 25°C. What is the solubility of CH₃Br_(g) in water at the same temperature and partial pressure of 0.164 bar?

Derive an expression to calculate molar mass of non-volatile solute by osmotic pressure measurement.

Derive an expression to calculate molar mass of non-volatile solute by osmotic pressure measurement.

What is Henry's law?

0.01 m aqueous formic acid solution freezes at – 0.021°C. Calculate its degree of dissociation, K_f = 1.86 K kg mol^–1.

Write the SI unit of the cryoscopic constant.

Calculate the mole fraction of solute, if the vapour pressure of pure benzene at a certain temperature is 640 mmHg and the vapour pressure of a solution of a solute in benzene is 600 mmHg.

How will you determine the molar mass of non-volatile solute by elevation of boiling point?