12. ALDEHYDES, KETONES AND CARBOXYLIC ACIDS Textbook Solution Class 12 – Chemistry

    1. Choose the most correct option.

    i. In the following resonating structures  A and B, the number of unshared electrons in valence shell present on oxygen respectively are

    In the following resonating structures Q 1.1 chapter 12

    a. 2, 4                     b. 2, 6
    c. 4, 6                     d. 6, 4

    Solution

    ii. In the Wolf -Kishner reduction, alkyl  aryl ketones are reduced to alkyl benzenes. During this change, ketones are first converted into

    a. acids

    b. alcohols
    c. hydrazones

    d. alkenes

    Solution

    iii. Aldol condensation is

    a. electrophilic substitution reaction
    b. nucleophilic substitution reaction
    c. elimination reaction
    d. addition – elimination reaction

    Solution

    iv. Which one of the following has lowest acidity ?

    iv. Which one of the following has lowest
    iv. Which one of the following has lowest 1
    Solution

    v. Diborane reduces
    a. ester group b. nitro group
    c. halo group d. acid group

    Solution

    vi. Benzaldehyde does NOT show positive test with
    a. Schiff reagent
    b. Tollens’ ragent
    c. Sodium bisulphite solution
    d. Fehling solution

    Solution

    2. Answer the following in one sentence

    i. What are aromatic ketones?

    Solution

    ii. Is phenyl acetic acid an aromatic carboxylic acid ?

    Solution

    iii. Write reaction showing conversion of ethanenitrile into ethanol.

    Solution
    iv. Predict the product of the following reaction:
    \[\ce{CH3 – CH2 – COOCH3->[i) AIH(i-Bu)_2][ii) H3O+]}\]?
    Solution

    v. Name the product obtained by reacting toluene with carbon monoxide and hydrogen chloride in presence of anhydrous aluminium chloride.

    Solution

    vi. Write reaction showing conversion of Benzonitrile into benzoic acid.

    Solution

    vii. Name the product obtained by the oxidation of 1,2,3,4-tetrahydronaphthalene with acidified potassium permanganate .

    Solution

    viii.What is formalin ?

    Solution

    ix. Arrange the following compounds in the increasing order of their boiling points :
    Formaldehyde, ethane, methyl alcohol.

    Solution

    x. Acetic acid is prepared from methyl magnesium bromide and dry ice in presence of dry ether. Name the compound which serves not only reagent but also as cooling agent in the reaction.

    Solution

    3. Answer in brief.

    i. Observe the following equation of reaction of Tollens’ reagent with  aldehyde. How do we know that a redox reaction has taken place. Explain.
    \[\ce{R-CHO + 2Ag(NH_{3})^{+}_{2} + OH^{-}->[\triangle] R-CO{O}^{-} + 2Ag↓ + 4NH3 + 2H2O}\]
    Solution

    ii. Formic acid is stronger than acetic acid. Explain.

    Solution

    iii. What is the action of hydrazine on cyclopentanone in presence of —. KOH in ethylene glycol ?

    Solution

    iv. Write reaction showing conversion of Acetaldehyde into acetaldehyde dimethyl acetal.

    Solution

    v. Aldehydes are more reactive toward nucleophilic addition reactions than ketones. Explain.

    Solution

    vi. Write reaction showing the action of the following reagent on propanenitrile –
    a. Dilute NaOH
    b. Dilute HCl ?

    Solution

    vii. Arrange the following carboxylic acids with increasing order of their acidic strength and justify your answer.

    vi. Arrange the following carboxylic acids
    vi. Arrange the following carboxylic acids
    Solution

    4. Answer the following

    i. Write a note on –
    a. Cannizaro reaction
    b. Stephen reaction

    Solution

    ii. What is the action of the following reagents on toluene ?
    a. Alkaline KMnO4 , dil. HCl and heat
    b. CrO2Cl2 in CS2
    c. Acetyl chloride in presence of anhydrous AlCl3.

    Solution

    iii. Write the IUPAC names of the following structures :

    Q 4.3 chapter 12
    Solution

    iv. Write reaction showing conversion of p- bromoisopropyl benzene into p-Isopropyl benzoic acid ( 3 steps).

    Solution

    v. Write reaction showing aldol condensation of cyclohexanone.

    Solution