Find CBSE Class 12 chemistry Solved Practice Paper (Set-2).These questions not only helps the students to prepare for exams in a better manner, but also help them in understanding the depth with which a topic should be studied.
Few Sample Questions from the Question Paper are given below:
Q. Why water has a much higher boiling point than hydrogen fluoride?
Ans. Since, in water molecule each H-atom can form H-bond with O atom of another water molecule thus forming a large cluster while in HF molecule each H-atom forms H-bond with F-atom of another HF molecule making a long chain of HF molecule. Hence, due to extensive hydrogen bonding between the water molecules, the boiling point of water is much greater than that of hydrogen fluoride.
Q. How the conductivity of an extrinsic semiconductor can be increased?
Ans. Conductivity of extrinsic semiconductor can be increased by doping. The conductivity of n-type semiconductor can be increased by doping it with pentavalent impurities like antimony and phosphorus and of p-type by doping it with trivalent impurities like boron and aluminium.
Q. What are food preservatives? Name two examples.
Ans. Food preservatives are certain compounds which prevents the spoilage of food due to the growth of microbes. Examples: Sodium benzoate and Sorbic acid.