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

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

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

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

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)

Define Freezing point.

The temperature at which vapour pressure of a liquid becomes equal to the atmospheric
pressure is _______.

(A) melting point

(B) boiling point

(C) 273 K

(D) 373 K

Which mixture is used for respiration by deep sea divers?

(A) He + O₂

(B) Ne + O₂

(C) Ar + O₂

(D) Kr + O₂

How does solubility of a gas in water varies with the temperature?

Derive the relation ∆H − ∆U = ∆nRT.

When KOH solution is added to potassium dichromate solution the colour of solution
changes to yellow, because _______

(A) chromate ion changes to dichromate ion

(B) dichromate ion changes to chromate ion

(C) oxidation number of chromium changes from + 6 to + 4

(D) oxidation number of chromium changes from + 4 to +6

How van’t Hoff factor is related to the degree of dissociation?

Which of the following 0.1 M aqueous solutions will exert the highest osmotic pressure?