Science (English Medium) Class 12 - CBSE Important Questions for Chemistry

Write the structure of an isomer of compound C₄H₉Br which is most reactive towards S_N1 reaction

Write the final product(s) in each of the following reactions:

Write the major products(s) in the following:

Write the major products(s) in the following:

What is the role of cryolite in the extraction of aluminium?

What is the role of limestone in the extraction of iron from its oxides?

Name the method used for the refining of zirconium.

What is the role of CO in the extraction of Iron?

Reduction of metal oxide to metal becomes easier if the metal obtained is in liquid state. Why?

Write the main products when n-butyl chloride is treated with alcoholic KOH.

Write the main products when methyl chloride is treated with AgCN.

What is the role of zinc metal in the extraction of silver ?

Describe the roles of the following: SiO₂ in the extraction of copper from copper matte

Describe the roles of the following: NaCN in froth floatation process

Name the method used for refining of copper metal.

Write the principle behind the froth floatation process. What is the role of collectors in this process?

What is meant by the term “chromatography”?

Outline the principles of refining of metals by the following method:

Vapour phase refining

Arrange the set of compounds in order of increasing boiling points.

Bromomethane, Bromoform, Chloromethane, Dibromomethane.

What are ambident nucleophiles? Explain with an example.