Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Chemistry

Assertion: Vitamin D can be stored in our body.

Reason: Vitamin D is fat-soluble vitamin.

Differentiate between the following:

Lyophobic Sol and Lyophilic Sol

When 19.5 g of F – CH₂ – COOH (Molar mass = 78 g mol⁻¹), is dissolved in 500 g of water, the depression in freezing point is observed to be 1°C. Calculate the degree of dissociation of F – CH₂ – COOH.

[Given: K_f for water = 1.86 K kg mol⁻¹]

Give a reason for the following observations:

Water soluble vitamins must be taken regularly in the diet.

Why is the value of van't Hoff factor for ethanoic acid in benzene close to 0.5?

Why is boiling point of 1 M NaCl solution more than that of 1 M glucose solution?

Assertion (A): Vitamin C cannot be stored in our body.

Reason (R): Vitamin C is fat soluble and is excreted from the body in urine.

The vitamins which can be stored in our body are ______.

Calculate Van't Hoff factor for an aqueous solution of K₃ [Fe(CN)₆] if the degree of dissociation (α) is 0.852. What will be boiling point of this solution if its concentration is 1 molal? (Kb = 0.52 K kg/mol)

What is the reason for the stability of colloidal sols?

Define the following term:

Zeta potential

Define the following terms: Associated colloids

Give reasons for the following observations:

Brownian movement provides stability to the colloidal solution.

Out of MgCl₂ and AlCl₃, which one is more effective in causing coagulation of negatively charged sol and why?

Out of BaCl₂ and KCl, which one is more effective in causing coagulation of a negatively charged colloidal Sol? Give reason.

Give reasons for the following observations: Leather gets hardened after tanning.

Write the structures of the following molecule: 

H₂SO₃

Define the following term : Brownian movement

Draw the structures of the following molecules: H₂S₂O₈

Account for the following : Cl – CH₂COOH is a stronger acid than CH₃COOH.