Subject

Chemistry

Class

ICSE Class 12

Pre Boards

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Sample Papers

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 Multiple Choice QuestionsShort Answer Type

21.

(i) Give the Clifford representation of constitution of bleaching powder.

(ii) Write the chemical reactions when bleaching powder reacts with dilute HCl.

(iii) What is responsible for its oxidizing as well as bleaching properties.

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22.

Complete the following reactions and name the type of reaction to which each belongs:

i) CH3Br KOH (aq) --->
ii) H2C=CH2 +HCl --->

iii right parenthesis space straight C subscript 2 straight H subscript 5 OH space rightwards arrow from 443 straight K to conc. space straight H subscript 2 SO subscript 4 of

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23.

(a) Write chemical equations for the following reactions and name the main product:  

(i) Formaldehyde with ammonia

(ii) Acetone with sodium hypoiodite

(iii) Oxalic acid with glycerol at 260°C.

(iv) Acetic anhydride with salicylic acid.


i) Formaldehyde reacts with ammonia to form hexamethylene tetramine. It is commercially known as urotropine and is used as urinary antiseptic.
6 HCHO space plus 4 NH subscript 3 space rightwards arrow stack left parenthesis CH subscript 2 right parenthesis subscript 6 straight N subscript 4 space with Hexamethylene space tetramine below plus space 6 straight H subscript 2 straight O


ii) Acetone reacts with sodium hypoiodite to form iodoform. It is a test for methyl ketones.



iii) Oxalic acid reacts with glycerol at 260°C to form allyl alcohol.



iv) Acetic anhydride reacts with salicylic acid to form ethyl benzoate and malonic acid.


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24.

 An aromatic compound ‘A’ on analysis was found to contain C, 79.14% and H, 5.66%. When ‘A’ is treated with alkali it does not turn brown or become polymerized but reacts as follows :    

2A + NaOH = X + Y

(b)In excess of dil HCl, bleaching powder liberates Cl2.
CaOCl2 +2HCl --> CaCl2 +H2O +Cl2

Where X = A + 2H; Y gives an acid, Z, on the addition of dilute HCl; here Z is Z = A + (O). Identify the compound ‘A’ and name the reaction it is undergoing by giving reasons in support of it.

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25.  How will you show the amphoteric nature of glycine ? Mention the pH value for its isoelectric point.
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26. How can primary, secondary and tertiary aliphatic amines be distinguished by reaction with HNO2 (NaNO2 + dilute H2SO4) ?
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27. How will you convert sorbitol into glucose ?
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28.

What are the reaction products of the following ?  

(ii) Why are same compounds not obtained at the final stage ?

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29.

Give the monomers of the following polymers :

(i) Teflon    (ii) Bakelite

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30.

Name the type of isomerism exhibited by the following pairs of compounds : 

(i) Acetaldehyde and vinyl alcohol

(ii) Maleic acid and fumaric acid.

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