Subject

Chemistry

Class

ICSE Class 12

Pre Boards

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Sample Papers

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 Multiple Choice QuestionsShort Answer Type

31.

Give a reason for the following:

Gelatin is added to ice creams.


32.

For the complex ion [Fe(CN)6]3-, state:

(i) The type of hybridisation

(ii) The magnetic behaviour

(iii) The oxidation number of the central metal atom


33.

Write the IUPAC name of [Co(en)2Cl2]+ ion and draw the structure of its geometrical isomers.


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34.

Explain why :

Mn2+ is more stable than Fe2+ towards oxidation to +3 state. (At. no. of Mn = 25, Fe = 26)


electronic configuration:

Mn = [Ar] 4s23d5
Mn2+ = [Ar]4s0 3d5

Electronic configuration:

Fe:[Ar] 4s23d6

Fe2+: 4s0 3d6

As shown in electronic congfiguration, Mn2+ has stable half filled d -subshell, whereas Fe2+ has a partially filled d- subshell hence as Fe2+ loses an electron and gets converted to Fe3+ it achieves stable half filled d-subshell. Therefore Mn2+ is more stable than Fe2+ towords oxidation +3 state.


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35.

Explain why:

Transition elements usually form coloured ions.


36.

Explain why:

Zr and Hf exhibit similar properties.


37.

Complete and balance the following chemical equations:(i) KMnO4 + KI + H2SO4   __+___+____+__(ii) K2Cr2O7 + H2SO4 + H2S   __ + ___+ ___+ __(iii) KMnO4 + H2SO4 + FeSO4   __ + ___+ ____ +__


38.

Arrange the following in the increasing order of their basic strength:

C2H5NH2, C6H5NH2, (C2H5)2NH


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39.

Give a balanced chemical equation of convert methyl cyanide to ethyl alcohol.


40.

What happens when benzene diazonium chloride reacts with phenol in weak alkaline medium? (Give balanced equation).


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