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

Explain column chromatography.

Name the common elements present in the anode mud in electrolytic refining of copper. Why are they so present?

What is meant by the term “chromatography”?

What criterion is followed for the selection of the stationary phase in chromatography?

Describe a method for refining nickel.

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

Vapour phase refining

Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.

Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?

Describe the preparation of potassium dichromate from iron chromite ore. What is the effect of increasing pH on a solution of potassium dichromate?

Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with iron (II) ions? Write the ionic equation for the reaction.

Give an example and suggest a reason for the following feature of the transition metal chemistry:

The lowest oxide of transition metal is basic, the highest is amphoteric/acidic.

Give an example and suggest a reason for the following feature of the transition metal chemistry:

A transition metal exhibits the highest oxidation state in oxides and fluorides.

Give an example and suggest a reason for the following feature of the transition metal chemistry:

The highest oxidation state is exhibited in oxoanions of a metal.

Indicate the steps in the preparation of K₂Cr₂O₇ from chromite ore.

Indicate the steps in the preparation of KMnO₄ from pyrolusite ore.

The hexaquo manganese(II) ion contains five unpaired electrons, while the hexacyanoion contains only one unpaired electron. Explain using Crystal Field Theory.

Draw figure to show the splitting of d orbitals in an octahedral crystal field.

How does the magnitude of Δ₀ decide the actual configuration of d orbitals in a coordination entity?

What are the monomeric repeating units of Nylon-6 and Nylon-6, 6?

What is a biodegradable polymer? Give an example of a biodegradable aliphatic polyester.