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Class 12 · Past paper

Chemistry 12 past paper 2023

41 published questions in this index. The full practice view lets you work through them and track your own attempts.

16 MCQs25 written questionsPractise this paper

Question index

  1. 1

    Which of the following has highest ionization energy?

    MCQ1 marksannual

  2. 1

    How can the following conversions be carried out? a. Nitrobenzene $\rightarrow$ Aniline b. Acetamide $\rightarrow$ Methylamine

    Part B3 marksannual

  3. 1

    Write mechanisms for **nitration** and **alkylation** of Benzene.

    Part C7 marksannual

  4. 2

    Which of the following oxides is acidic?

    MCQ1 marksannual

  5. 2

    Differentiate between **Ethanol**, **2-Propanol** and **2-Methyl-2-Propanol** on the basis of **Lucas test**.

    Part B3 marksannual

  6. 2

    What is **Global warming**? Write three adverse effects of each 'global warming' and 'acid rain' on environment.

    Part C6 marksannual

  7. 3

    $Pb^{+4}$ compounds are good:

    MCQ1 marksannual

  8. 3

    Write mechanism of the reaction when two molecules of formaldehyde react with each other in the presence of NaOH.

    Part B3 marksannual

  9. 3

    What is **esterification**? Write mechanism for the acid catalyzed reaction between methanol and acetic acid.

    Part C7 marksannual

  10. 4

    Carboxylic acids can be prepared by the reactions of Grignard reagent with:

    MCQ1 marksannual

  11. 4

    Write the preparation of **Ethanol** and **2-Propanol** from **Grignard reagent**.

    Part B3 marksannual

  12. 4

    Briefly explain the effect of: i. **Temperature** ii. **pH** and iii. **Substrate concentration** on enzyme activity along with general graphical representation for each factor.

    Part C6 marksannual

  13. 5

    To what category of molecules do enzymes belong?

    MCQ1 marksannual

  14. 5

    How is **Nylon 6,6** prepared by condensation polymerization? Write its equations.

    Part B3 marksannual

  15. 5

    Differentiate **beryllium (Be)** from other members of its group in terms of its behavior of: i. Nitrides, ii. Carbides, iii. Oxides, iv. Reaction with alkalies, v. Reaction with h…

    Part C7 marksannual

  16. 6

    Peroxyacetyl Nitrate (PAN) is an irritant to human beings and it affects:

    MCQ1 marksannual

  17. 6

    Enlist the raw materials used for the preparation of lipstick.

    Part B3 marksannual

  18. 6

    Explain three differences using **'Kinetic evidence'**, **'Stereochemical evidence'** and **'Structure of substrate'** between $SN_2$ and $SN_1$ reactions.

    Part C6 marksannual

  19. 7

    Chemically nail polish remover is:

    MCQ1 marksannual

  20. 7

    Briefly explain the trends in solubility of the hydroxides and sulphates of group II elements.

    Part B3 marksannual

  21. 8

    Which of the following electronic transitions requires **highest amount of energy** when a compound is interacted with ultraviolet radiations?

    MCQ1 marksannual

  22. 8

    Write any three advantages of atomic emission spectroscopy.

    Part B3 marksannual

  23. 9

    Height of peak in mass spectrum shows:

    MCQ1 marksannual

  24. 9

    Identify any three types of **electronic transitions** in **Formaldehyde** ($H_2C=O$) when it is subjected to ultraviolet radiations.

    Part B3 marksannual

  25. 10

    Which of the following will **NOT** give iodoform test?

    MCQ1 marksannual

  26. 10

    How can **Ethanol** and **Acetone** be identified by **IR spectrum**?

    Part B3 marksannual

  27. 11

    Oxidation of 2-propanol gives:

    MCQ1 marksannual

  28. 11

    Write chemical equations for the preparation of acetone by hydration of a suitable alkyne.

    Part B3 marksannual

  29. 12

    Nitration of phenol takes place at ___ than benzene.

    MCQ1 marksannual

  30. 12

    Briefly describe two causes that explain the inert nature of alkanes towards polar reagents.

    Part B3 marksannual

  31. 13

    Reaction of alcohols with sodium metal gives:

    MCQ1 marksannual

  32. 14

    Geometrical isomerism is shown by:

    MCQ1 marksannual

  33. 14

    What is a homologous series? Write its two characteristics.

    Part B3 marksannual

  34. 15

    Which of the following alkynes is acidic in nature?

    MCQ1 marksannual

  35. 15

    Write names of the following **coordination compounds**: a. $Na_4[Mn(CN)_6]$ b. $Cr[(NO_2)_3(NH_3)_3]$ c. $[Ni(CO)_4(F)_2]SO_4$

    Part B3 marksannual

  36. 16

    Why are Zn²⁺ complexes colorless? Explain briefly with the help of d-d transitions phenomenon.

    Part B3 marksannual

  37. 17

    The oxidation state of central metal ($Mn$) in the following complex $Na[Mn(CO)_5(F)_2]$ is:

    MCQ1 marksannual

  38. 17

    Why is the ionization energy of nitrogen greater than that of oxygen, although ionization energy generally increases along the period?

    Part B3 marksannual

  39. 18

    Write chemical reactions to show the **amphoteric nature** of $Al_2O_3$.

    Part B3 marksannual

  40. 19

    Why is $K_2CO_3$ more stable than $Li_2CO_3$? Support your answer in terms of the polarizing ability of the positive ion.

    Part B3 marksannual

  41. 20

    Why is $CCl_4$ insoluble and $SiCl_4$ soluble in water? Explain your answer by writing mechanism for hydrolysis of group IV halides.

    Part B3 marksannual

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