Complete CBSE Class 12 Chemistry Exam Package for the last Moment

Feb 18, 2014, 14:20 IST

Fined all the previous year solved and unsolved question papers, guess papers, Syllabus and Important questions of class 12 Chemistry for the last moment and refresh your study in few minutes

Complete CBSE Class 12 Chemistry Exam Package for the last Moment, given here

Q. what is meant by 'doping' in a semiconductor?

Answer.
Doping: - It is adding appropriate amount of suitable impurities in the semiconductor

Q. what is the role of graphite in the electrometallurgy of aluminium?

Answer.
Graphite is used as both anode as well as cathode. It prevents the formation of oxygen gas.

Q. What are the following substances? Give one example of each one of them.
(1) Tranquilizers
(ii) Food preservatives
(iii) Synthetic detergents

Answer.
a.Tranquilizers: - These are a class of compounds which are used for the treatment of stress, mild or even severe mental diseases. For example- veronal, etc.

b.Food preservatives: - They prevent spoilage of food due to microbial growth. For example- sodium benzoate.

c.Synthetic detergents: - these are cleansing agents which have all the properties of soaps but do not contain any soap. For example- Sodium laurylsuiphate.