HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Important Questions for Chemistry

What is the freezing point of a liquid? The freezing point of pure benzene is 278.4 K. Calculate the freezing point of the solution when 2.0 g of a solute having molecular weight 100 g mol^-1
 is added to 100 g of benzene.
( K_f of benzene = 5.12 K kg mol^-1 .) 

4.0 grams of NaOH ( Molar mass = 40.0 g mol^-1 ) is dissolved in 500 cm³ of water. What is the molarity of NaOH solution? 

Choose the most correct option.

In calculating osmotic pressure the concentration of solute is expressed in _______.

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In calculating osmotic pressure the concentration of solute is expressed in _______.

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A living cell contains a solution which is isotonic with 0.3 M sugar solution. What osmotic pressure develops when the cell is placed in 0.1 M KCl solution at body temperature?

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A living cell contains a solution which is isotonic with 0.3 M sugar solution. What osmotic pressure develops when the cell is placed in 0.1 M KCl solution at body temperature?

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Pressure cooker reduces cooking time for food because _______.

Answer the following in one or two sentences.

What is osmotic pressure?

Answer the following in one or two sentences.

What is osmotic pressure?

Answer the following.

What are isotonic and hypertonic solutions?

Answer the following.

What are isotonic and hypertonic solutions?

Derive the relationship between the degree of dissociation of an electrolyte and van’t Hoff factor.

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?

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. 

State Henry’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.