CBSE Class 12 Chemistry Question Paper 2008 Delhi Set 56 1

CBSE CLASS XII Questions

• 1.

  (i) A first order reaction is 20% complete in 10 minutes. Calculate the time taken when 80% of the reaction will be completed.

  [Given : log 5 = 0.7, log 4 = 0.6]

  (ii) For a chemical reaction \( \mathrm{R \rightarrow P} \), variation in \( \ln[\mathrm{R}] \) vs. time (t) graph is given below :

  (I) Predict the order of the reaction.

  (II) Write the slope of the curve.

  
  

  

  
  

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• 2.

  (a) Define 'Denatured Protein' with an example.

  (b) What happens when glucose reacts with HCN ? Write the reaction involved.

  (c) Name the disease caused by the deficiency of Vitamin C.

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• 3.

  (i) Give a chemical test to distinguish between Propanal and Propanone.

  (ii) Which of the given acids is stronger and why ? \( \mathrm{F_3C{-}C_6H_4{-}COOH} \) or \( \mathrm{H_3C{-}C_6H_4{-}COOH} \)

  (iii) Complete the given reaction sequence :

  \[ \mathrm{CH_3CH_2CH_2COOC_2H_5} \xrightarrow{\mathrm{NaOH}} \mathrm{A + C_2H_5OH} \]

  \[ \mathrm{A} \xrightarrow{\mathrm{H_3O^+}} \mathrm{B} \]

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• 4.

  Conductivity of \( 2.5 \times 10^{-4} \) M methanoic acid solution is \( 5.25 \times 10^{-5} \) S cm\(^{-1}\).

  (a) Calculate its molar conductivity.

  (b) Calculate its degree of dissociation.

  [Given : \( \lambda^{\circ}_{(\mathrm{H^+})} = 349.5 \) S cm\(^2\) mol\(^{-1}\) and \( \lambda^{\circ}_{(\mathrm{HCOO^-})} = 50.5 \) S cm\(^2\) mol\(^{-1}\)]

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• 5.

  Write the reactions taking place at anode and cathode in a lead storage battery, when it is in use.

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• 6.

  An organic compound (X) has the molecular formula \(C_5H_{10}O\). Draw structures for (X) if it:
  (I) does not give Tollen's test but gives a positive iodoform test.
  (II) does not give Tollen's test and iodoform test but undergoes Aldol condensation.
  (III) undergoes Cannizzaro's reaction.
  

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