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

Which of the following polymers soften on heating and harden on cooling? What are the polymers with this property collectively called? What are the structural similarities between such polymers? Bakelite, urea-formaldehyde resin, polythene, polyvinyls, polystyrene.

How would you account for the following:

There is a greater range of oxidation states among the actinoids than among the lanthanides.

Name the suitable alcohol and reagent, from which 2-Chloro-2-methyl propane can be prepared.

Write the equations for the following reaction:

Tert butyl chloride is treated with sodium ethoxide.

Why does the cell voltage of a mercury cell remain constant during its lifetime?

Write any two consequences of Lanthanoid Contraction.

Which of the following reactions are feasible?

Give reasons:

Mercury cell delivers a constant potential during its life time.

Write the mechanism of the following reaction:

\[\ce{2CH3CH2OH ->[H^+][413 K] CH3-CH2-O-CH2-CH3 + H2O}\]

Draw the zwitter ion structure for sulphanilic acid.

Give a reason for the following observations:

Amino acids behave like salts.

A non-volatile solute 'X' (molar mass = 50 g mol₋₁), when dissolved in 78 g of benzene, reduced its vapour pressure to 90%. Calculate the Mass of X dissolved in the solution.

Write the name of the reaction, structure and IUPAC name of the product formed when:

\[\ce{CH3CH2CH(CH3)CH(CH3) ONa}\] reacts with \[\ce{C2H5Br}\]

The vapour pressure of pure water at a certain temperature is 23.80 mm Hg. If 1 mole of a non-volatile non-electrolytic solute is dissolved in 100g water, Calculate the resultant vapour pressure of the solution.

Name an important alloy which contains some of the lanthanoid metals.

Name an important alloy which contains some of the lanthanoid metals. Mention its uses.

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: