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CBSE Class 12th Chemistry Set I solved Question Paper 2012

Dec 13, 2012 11:36 IST

CBSE Chemistry Set- I Solved Question Paper 2012, given here.

Here you can find Chemistry Solved Question Paper. Save your time and take the help while solving the Chemistry question paper set-I this paper will help you in scoring exceptionally well mark in Chemistry paper

Some solved questions from CBSE Class 12th Chemistry Question Paper (Set-I) are given here

Q. How the conductivity of an intrinsic semiconductor may be increased?

Answer. The conductivity of an intrinsic semiconductor can be increased by doping that is adding appropriate amount of suitable impurities in the semiconductor.

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Q. Define ‘Peptization’.

Answer. Peptization: - It can be defined as the process of converting a precipitate into colloidal sol by shaking it with dispersion medium in the presence of small amount of electrolyte. The electrolyte used is known as peptizing agent.

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Q. How is copper extracted from a low grade ore of it?

Answer. Copper can be extracted from a low grade ore of it through the process of bacterial leaching.

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Q. Differentiate between disinfectants and antiseptics.

Answer. Antiseptics: - They are applied to the living tissues such as wounds, cuts. For example-dettol, iodoform

Disinfectants: - They are applied to inanimate objects such as floors. For example-   sulphur dioxide in very low concentration.

Same substance can act as an antiseptic & disinfectant by varying the concentration.

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Q. Which methods are usually employed for purifying the following metals:
(i) Nickel
(ii) Germanium
Mention the principle behind each one of them?

Answer. I. Nickel can be extracted with the help of mond process.

Principle of Mond Process: - in this method the metal is converted into its volatile compound & collected elsewhere. After that it is decomposed to give pure metal.

II. Germanium is extracted with the help of zone refining.

Principle of Zone Refining: - this method is based on the fact that the impurities are more soluble in the melt than in the solid state of the metal.

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Q. What are food preservatives? Name two such substances.

Answer. Food preservatives: - They help in preventing spoilage of food due to microbial growth. For example-table salt, sugar, vegetable oils, sodium benzoate etc.

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