For a reversible reaction Kp/Kc =(RT)\(\bigtriangleup\)n at 300K. If Kc/Kp=14941.5 (in litre atm unit) for a given reaction then \(\bigtriangleup\)n for the reaction is  [Given that log Kp/Kc =4.17 and log(24.93)=1.39]

CBSE CLASS XII Related Questions

  • 1.

    (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 :

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

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


      • 2.

        (i) (I) The \(\mathrm{pK_b}\) value of aniline is higher than that of methylamine. Explain why.

        (II) Arrange the following compounds in decreasing order of their basic strength in the gaseous phase :

        \(\mathrm{NH_3}\), \(\mathrm{(C_2H_5)_2NH}\), \(\mathrm{(C_2H_5)_3N}\), \(\mathrm{C_2H_5NH_2}\)

        (III) What is Hinsberg's reagent ? Mention its one use.

        (ii) How will you convert the following :

        (I) Nitrobenzene to Benzenediazonium chloride ?

        (II) Iodomethane to Ethanamine ?


          • 3.

            (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.




              • 4.
                Consider the decomposition of hydrogen peroxide \( (\mathrm{H_2O_2}) \) as per the equation given below : \[ 2\mathrm{H_2O_2} \xrightarrow[\text{Alkaline medium}]{I^-} 2\mathrm{H_2O} + \mathrm{O_2} \] The mechanism for this reaction was found to be : Step I : \( \mathrm{H_2O_2} + I^- \longrightarrow \mathrm{H_2O} + IO^- \) (slow) Step II : \( \mathrm{H_2O_2} + IO^- \longrightarrow \mathrm{H_2O} + I^- + \mathrm{O_2} \) (fast) (a) Write the rate law expression. (b) Determine the order of reaction with respect to \( \mathrm{H_2O_2} \), \( I^- \) and overall order of reaction. (c) What is the molecularity of the reaction in Step II ?


                  • 5.

                    (a) Write two structural differences between DNA and RNA.

                    (b) Which component of starch is a branched chain polymer of \( \alpha \)-D-(+)-glucose ? Write its one characteristic feature.

                    (c) Which types of bonds hold the polypeptide chains in fibrous proteins ?


                      • 6.

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

                          CBSE CLASS XII Previous Year Papers

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