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

Describe the following:

Decarboxylation

Comment on the nature of two S−O bonds formed in SO₂ molecule. Are the two S−O bonds in this molecule equal?

How is the presence of SO₂ detected?

How is SO₂ an air pollutant?

What is the reason for the stability of colloidal sols?

Define the following term:

Zeta potential

Define the following terms: Associated colloids

Give reasons for the following observations:

Brownian movement provides stability to the colloidal solution.

Out of MgCl₂ and AlCl₃, which one is more effective in causing coagulation of negatively charged sol and why?

Out of BaCl₂ and KCl, which one is more effective in causing coagulation of a negatively charged colloidal Sol? Give reason.

Give reasons for the following observations: Leather gets hardened after tanning.

Write the structures of the following molecule: 

H₂SO₃

Define the following term : Brownian movement

Draw the structures of the following molecules: H₂S₂O₈

Account for the following : Cl – CH₂COOH is a stronger acid than CH₃COOH.

A group 14 element is to be converted into n-type semiconductor by doping it with a suitable impurity. To which group should this impurity belong?

What is a semiconductor?

Non-stoichiometric cuprous oxide, Cu₂O can be prepared in laboratory. In this oxide, copper to oxygen ratio is slightly less than 2 : 1. Can you account for the fact that this substance is a p-type semiconductor?

Classify each of the following as being either a p-type or a n-type semiconductor:

1. Ge doped with In 
2. B doped with Si