Subject

Chemistry

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

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 Multiple Choice QuestionsShort Answer Type

1.

Give one example each of 'oil in water' and 'water in oil' emulsion.

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2.

Which reducing agent is employed to get copper from the leached low-grade copper ore?

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3.

Which of the following is a more stable complex and why?

 (i) [Co(NH3)6]3+

 (ii) [Co(en)3]3+

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4.

An element with density 11.2 g cm-3  forms a f.c.c. lattice with edge length of 4 x10-8

Calculate the atomic mass of the element. (Given:  NA = 6.022x 10-23 (mol-1

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5.

Examine the given defective crystal:
 

Answer the following questions:


(i) What type of stoichiometric defect is shown by the crystal?

(ii) How is the density of the crystal affected by this defect?

 (iii) What type of ionic substances shows such defect? 

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6.

Calculate the mass of compound (molar mass = 256 g mol-1) to be dissolved in 75 of benzene to lower its freezing point by 0.48 K (Kf= 5.12 kg mol-1 )

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7.

Define an ideal solution and write one of its characteristics.


Definition:  The solutions that obey Raoult’ s law over the entire range of concentration are called ideal solutions. Examples:  n-hexane and n-heptane.

Characteristics: For ideal solutions: 

 Enthalpy of mixing (mixH) of the pure components to form the solution is zero.

The volume of mixing (mixV) is also equal to zero. 

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8.

Write two differences between 'order of reaction' and 'molecularity of reaction?

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9.

Outline the principles behind the refining of metals by the following methods:

Zone refining method

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10.

Outline the principles behind the refining of metals by the following methods:

Chromatographic method 

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