Science (English Medium) Class 12 - CBSE Question Bank Solutions

Write the name of reagent and equation for the preparation of the following ether by Williamson’s synthesis:

2-Methoxy-2-methylpropane

8 g of glucose, C₆H₁₂O₆ (Molar Mass = 180 g mol⁻¹) is dissolved in 1 kg of water in a sauce pan. At what temperature will this solution boil? 

(K_b for water = 0.52 K kg mol⁻¹, boiling point of pure water = 373.15 K)

Calculate the boiling point of solution when 4g of MgSO₄ (M= 120 g mol^-1) was dissolved in 100g of water, assuming MgSO4 undergoes complete ionization. (K_b for water = 0.52 K kgmol^-1)

Write the structures of A and B in the following reactions

Predict the products of the following reactions:

Illustrate the following reaction giving suitable example in each case: Diazotisation

On adding NaOH to ammonium sulphate, a colourless gas with pungent odour is evolved, which forms a blue-coloured complex with Cu²⁺ ion. Identify the gas.

Out of 1 M glucose and 2 M glucose, which one has a higher boiling point and why?

Name the reagents used in the following reactions:

Why is elevation of boiling point a colligative property?

Define the following term: 

Molal elevation constant (K_b)

Based on molecular forces, what type of polymer is neoprene?

Explain the following term with suitable examples: 

Frenkel defect

Explain the following term with a suitable example:

Interstitials

Boiling point of water at 750 mm Hg is 99.63°C. How much sucrose is to be added to 500 g of water such that it boils at 100°C? Molal elevation constant for water is 0.52 K kg mol⁻¹.

Write the chemistry of recharging the lead storage battery, highlighting all the materials that are involved during recharging.

Explain the term with suitable examples:

Alcosol

Explain the term with suitable examples:

Aerosol

Explain the term with suitable examples:

Hydrosol

Aqueous copper sulphate solution (blue in colour) gives a green precipitate with aqueous potassium fluoride. Explain this experimental result.