Subject

Chemistry

Class

ICSE 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

31.

How will you convert the following (write the relevant equations) :
Glucose to osazone.

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32. Compare the components that constitute DNA and RNA.  
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 Multiple Choice QuestionsLong Answer Type

33. Define osmotic pressure. Arrange the following in increasing order of osmotic pressure and give reasons in support of your answer :
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34.

A cell is constructed by dipping a zinc rod in 0.1 M zinc nitrate solution and a lead rod in 0.2 M lead nitrate solution. E°pb2+/pb =-0.13 V and E°Zn2+/ Zn=–0.76 V. [3]

(i) Write the spontaneous cell reaction.

(ii) Calculate standard emf and emf of the cell.

(b) Explain the purification of common salt by bubbling hydrogen chloride gas through its solution.


(i) Spontaneous cell reaction is as follows :

At space anode space space space space space space space space space Zn space rightwards arrow space Zn to the power of plus space plus 2 straight e to the power of minus space straight E space equals plus 0.76 space straight V
At space cathode space space space space space space Pb to the power of 2 plus end exponent space plus 2 straight e to the power of minus rightwards arrow Pb space straight E space equals negative 0.12 straight V
Cell space reaction colon space Zn space plus Pb to the power of 2 plus end exponent space rightwards arrow Zn to the power of 2 plus end exponent space plus Pb

ii right parenthesis space Standard space emf space of space cell space left parenthesis straight E subscript cell superscript 0 right parenthesis space equals space straight E subscript anode space plus straight E subscript cathode

equals space 0.76 space plus left parenthesis negative 0.13 right parenthesis space equals space 0.76 minus 0.13 space equals plus 0.63 space volt
Emf space of space cell space left parenthesis straight E subscript cell right parenthesis space space equals straight E subscript cell superscript 0 space minus fraction numerator 0.0591 over denominator straight n end fraction space log fraction numerator left square bracket products right square bracket over denominator left square bracket reactants right square bracket end fraction

equals space 0.63 minus fraction numerator 0.0591 over denominator 2 end fraction log space fraction numerator left square bracket Zn to the power of 2 plus end exponent right square bracket over denominator left square bracket Pb to the power of 2 plus end exponent right square bracket end fraction space equals space 0.63 minus 0.0295 space log 1 half

straight E subscript cell space equals space 0.63 minus 0.0295 space log space 1 half
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35.

Give one test each to distinguish between the following pairs. Write the relevant equations.   

(i) Benzoic acid and phenol

(ii) Glucose and fructose

(iii) Acetophenone and benzophenone.

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