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

Illustrate the following reactions giving suitable example in each case 

Acetylation of amines

Define the following terms: Rate constant

An element with density 11.2 g cm^–3 forms a f.c.c. lattice with edge length of 4 × 10^–8 cm.
Calculate the atomic mass of the element.
(Given : N_A = 6.022 × 10²³ mol^–1)

Outline the principles behind the refining of metals by the following methods:

Zone refining method

Outline the principles behind the refining of metals by the following methods:

Chromatographic method

Write the principle behind the following methods of refining:

Vapour-phase refining

How will you convert the following?

Aniline into N−phenylethanamide

Explain the following terms :

Rate constant (k)

What is the difference between a glycosidic linkage and a peptide linkage? 

 Out of 0.1 molal aqueous solution of glucose and 0.1 molal aqueous solution of KCl, which one will have higher boiling point and why? 

 A solution 0.1 M of Na₂SO₄ is dissolved to the extent of 95%. What would be its osmotic pressure at 027 ? C (R = 0.0821 L atm K^-1 mol^-1) .

Write down the reaction taking place in blast furnace related to the metallurgy of iron in the temperature rnge 500 K – 800 K. What is the role of limestone in the metallurgy of iron? 

What happens when Silver is leached with NaCN in the presence of air? 

What happens when Copper matte is charged into silica lined converter and hot air blast is blown? 

What happens when NaCN is added in an ore containing PbS and ZnS during concentration by froth floatation method? 

 Why is alpha (α) hydrogen of carbonyl compounds acidic in nature?

An element crystallizes in fcc lattice with a cell edge of 300 pm. The density of the element is 10.8 g cm^-3. calculate the number of atoms in 108 g  of the element.

Name the method of refining which is Used to obtain semiconductor of high purity. 

Name the method of refining which is Used to obtain low boiling metal.

Write chemical equations of the following reaction : 

Propanone is treated with dilute Ba (OH)_2-.