Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions

The vitamins absorbed from intestine along with fats are ____________.

We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentrations 0.1 M, 0.01 M and 0.001 M, respectively. The value of van’t Hoff factor for these solutions will be in the order ______.

Sulphur trioxide can be obtained by which of the following:

Which of the following oxides shows electrical properties like metals?

The values of Van’t Hoff factors for KCl, NaCl and K₂SO₄, respectively, are ______.

Van’t Hoff factor i is given by the expression:

(i)  i = `"Normal molar mass"/"Abnormal molar mass"`

(ii)  i = `"Abnormal molar mass"/"Normal molar mass"`

(iii) i = `"Observed colligative property"/"Calculated colligative property"`

(iv) i =  `"Calculated colligative property"/"Observed colligative property"`

Which of the following interface cannot be obtained?

Method by which lyophobic sol can be protected?

Which of the following colloids cannot be coagulated easily?

(i) Lyophobic colloids.

(ii) Irreversible colloids.

(iii) Reversible colloids.

(iv) Lyophilic colloids.

What happens when gelatin is mixed with gold sol?

Match the items given in Column I and Column II.

A hydrocarbon ‘A’, \[\ce{(C4H8)}\] on reaction with \[\ce{HCl}\] gives a compound ‘B’, \[\ce{(C4H9Cl)}\], which on reaction with 1 mol of \[\ce{NH3}\] gives compound ‘C’, \[\ce{(C4H11N)}\]. On reacting with \[\ce{NaNO2}\] and \[\ce{HCl}\] followed by treatment with water, compound ‘C’ yields an optically active alcohol, ‘D’. Ozonolysis of ‘A’ gives 2 mols of acetaldehyde. Identify compounds ‘A’ to ‘D’. Explain the reactions involved.

Which of the following B group vitamins can be stored in our body?

Why must vitamin C be supplied regularly in diet?

Match the vitamins given in Column I with the deficiency disease they cause given in Column II.

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?