PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions for Chemistry

Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with iodide.

For M²⁺/M and M³⁺/M²⁺ systems, the E° values for some metals are as follows:

Use this data to comment upon:

1. The stability of Fe³⁺ in acid solution as compared to that of Cr³⁺ or Mn³⁺ and
2. the ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.

Predict which of the following will be coloured in the aqueous solution?

Ti³⁺, V³⁺, Cu⁺, Sc³⁺, Mn²⁺, Fe³⁺ and Co²⁺. Give reasons for each.

Compare the stability of +2 oxidation state for the elements of the first transition series.

How would you account for the following:

Of the d⁴ species, Cr²⁺ is strongly reducing while manganese (III) is strongly oxidising.

How would you account for the following:

Cobalt (II) is stable in aqueous solutions, but in the presence of complexing reagents, it is easily oxidised.

How would you account for the following:

The d¹ configuration is very unstable in ions.

What is meant by ‘disproportionation’? 

Which metal in the first series of transition metals exhibits +1 oxidation state most frequently and why?

Calculate the number of unpaired electrons in the following gaseous ions:

Mn³⁺, Cr³⁺, V³⁺ and Ti³⁺. Which one of these is the most stable in an aqueous solution?

What are alloys?

What are inner transition elements?

Use Hund’s rule to derive the electronic configuration of Ce³⁺ ion and calculate its magnetic moment on the basis of ‘spin-only’ formula.

Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following point:

Electronic configurations

Write down the number of 3d electrons in the following ion:

Cu²⁺

Indicate how would you expect the five 3d orbitals to be occupied for this hydrated ion (octahedral).

Comment on the statement that elements of the first transition series possess many properties different from those of heavier transition elements.

What can be inferred from the magnetic moment value of the following complex species?

Classify the following as addition and condensation polymers: Terylene, Bakelite, Polyvinyl chloride, Polythene.

Explain the difference between Buna-N and Buna-S

Distinguish between the terms homopolymer and copolymer and give an example of each.