HSC Science (Electronics) इयत्ता १२ वी - Maharashtra State Board Important Questions for Chemistry

1.0 x10^-3Kg of urea when dissolved in 0.0985 Kg of a solvent, decreases freezing point of the solvent by 0.211 k. 1.6x10 Kg of another non-electrolyte solute when dissolved in 0.086 Kg of the same solvent depresses the freezing point by 0.34 K. Calculate the molar mass of the another solute. (Given molar mass of urea = 60)

The substance ‘X’, when dissolved in solvent water gave molar mass corresponding to the molecular formula ‘X3’. The van’t Hoff factor (i) is _______.

(A) 3

(B) 0.33

(C) 1.3

(D) 1

A solution of glucose in water is labelled as 10% (W/W).

Calculate:

a. Molality

b. Molarity of the solution.

[Given: Density of solution is 1.20 g mL^-1 and molar mass of glucose is 180 g mol^-1 ]

The boiling point of water at high altitude is low. because________________ .

(a) the temperature is low.                                         

(b) the atmospheric pressure is low.

(c) the temperature is high.

(d) the atmospheric pressure is high

A solution containing 0.73 g of camphor (molar mass 152 g . mol^-1) in 36.8 g of acetone (boiling point 56.3°C) boils at 56.55°C. A solution of 0.564 g of unknown compound in the same weight of acetone boils at 56.46^oC. Calculate the molar mass of the unknown compound.

Define Cryoscopic constant.

Determine the osmotic pressure of a solution prepared by dissolving 2.5 × 10⁻² g of K₂SO₄ in 2L of water at 25°C, assuming that it is completely dissociated.

(R = 0.0821 L atm K⁻¹ mol⁻¹, Molar mass of K₂SO₄ = 174 g mol⁻¹)

Determine the osmotic pressure of a solution prepared by dissolving 2.5 × 10⁻² g of K₂SO₄ in 2L of water at 25°C, assuming that it is completely dissociated.

(R = 0.0821 L atm K⁻¹ mol⁻¹, Molar mass of K₂SO₄ = 174 g mol⁻¹)

Which of the following solutions shows maximum depression in freezing point?

(A) 0.5 M Li₂SQ₄

(B) 1 M NaCl

(C) 0.5 M A1₂(SO₄)₃

(D) 0.5 MBaC1₂

Calculate the mole fraction and molality of HNO₃ in solution contaning 12.2%HNO₃ (Given atomic mases:H=1, N=13,O=16)

Calculate the amount of CaCl₂ (van't Hoff factor i = 2.47) dissolved in 2.5 L solution so that its osmotic pressure at 300K is 0.75 atmosphere.

Given : Molar mass of CaCl₂ is 111g mol^-1

R=0.082 L.atm K^-1mol^-1

Explain, why do aquatic animals prefer to stay at lower level of water during summer?

Which of the following is not a colligative property?

Which of the following is not a colligative property?

Gas (A) is more soluble in water than Gas (B) at the same temperature. Which one of the two gases will have the higher value of KH (Henry’s constant) and why

Why do gases always tend to be less soluble in liquids as the temperature is raised?

Calculate the amount of CaCl₂ (molar mass = 111 g mol⁻¹) which must be added to 500 g of water to lower its freezing point by 2 K, assuming CaCl₂ is completely dissociated. (K_f for water = 1.86 K kg mol⁻¹)

A solution of a substance having mass 1.8 x 10^-3 kg has the osmotic pressure of 0.52 atm at 280 K. Calculate the molar mass of the substance used.
[Volume = 1 dm³, R = 8.314 J K^-1 mol^-1]

The boiling point of benzene is 353.23 K. When 1.80 gram of non-volatile solute  was dissolved in 90 gram of benzene, the boiling point is raised to 354.11 K. Calculate the molar mass of solute.
[Kb for benzene = 2.53 K kg mol^-1]

An organic substance (M = 169 gram mol^–1) is dissolved in 2000 cm³ of water. Its osmotic pressure at 12°C was found to be 0.54 atm. If R = 0.0821 L atm K^–1 mol^–1, calculate the mass of the solute.