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.

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

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2.

What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 1/3rd of tetrahedral voids?

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3.

What is the basicity of H3PO4?

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4.

 What is meant by positive deviations from Raoult's law? Give an example. What is the sign of mixH for positive deviation?

OR

Define azeotropes. What type of azeotrope is formed by positive deviation from Raoult's law? Give an example.


The solutions that do not obey Raoult’s law over the entire range of concentration are known as non-ideal solutions. They have vapour pressures either higher or lower than those predicted by Raoult’s law. If the vapour pressure is higher, then the solution is said to exhibit a positive deviation from Raoult’s law.

 A mixture of ethanol and acetone is an example of a solution that shows a positive deviation from Raoult’s law.

 In case of solutions showing positive deviations, absorption of heat takes place that  mixH has a positive sign.

 OR

Azeotropes are the binary mixtures of solutions that have the same composition in liquid and vapour phases and that have constant boiling points.

 A minimum-boiling azeotrope is formed by solutions showing a large positive deviation from Raoult’s law at a specific composition.

 Example: An ethanol–water mixture containing approximately 95% ethanol by volume

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5.

Following reactions occur at cathode during the electrolysis of aqueous silver chloride solution:


Ag+ (aq) + e-  →  Ag(s)          E° = +0.80 V

 H+ (aq) + e-   → 1/2 H2 (g)     E° = 0.00 V

 On the basis of their standard reduction electrode potential (E°) values, which reaction is feasible at the cathode and why?

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6.

Define limiting molar conductivity. Why conductivity of an electrolyte solution decreases with the decrease in concentration?

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7.

What are the transition elements? Write two characteristics of the transition elements ?

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8.

Write down the IUPAC name of the following complex:


[Cr(NH3)2Cl2(en)]Cl    (en = ethylenediamine)

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9.

Write the formula for the following complex:


Pentaamminenitrito-o-Cobalt (III)

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10.

Draw the geometrical isomers of complex [Pt(NH3)2Cl2]? 

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