Aldehydes, Ketones, and Carboxylic Acids — Chemistry STD 12 Science — Question

Read the passage given below and answer the following questions:

When an aldehyde with no et-hydrogen reacts with concentrated aqueous NaOH, half the aldehyde is converted to carboxylic acid salt and other half is converted to an alcohol. In other words, half of the reactant is oxidized and other half is reduced. This reaction is known as Cannizzaro reaction.

The following questions are multiple choice questions. Choose the most appropriate answer:

1. A mixture of benzaldehyde and formaldehyde on heating with aqueous NaOH solution gives:

1. Benzyl alcohol and sodium formate.
2. Sodium benzoate and methyl alcohol.
3. Sodium benzoate and sodium formate.
4. Benzyl alcohol and methyl alcohol.

2. Which of the following compounds will undergo Cannizzaro reaction?

1. CH₃CHO
2. CH₃COCH₃
3. C₆H₅CHO
4. C₆H₅CH₂CHO

3. Trichloroacetaldehyde is subjected to Cannizzaro's reaction by using NaOH. The mixture of the products contains sodium trichloroacetate ion and another compound. The other compounds is:

1. 2, 2, 2-trichloroethanol.
2. Trichloromethanol.
3. 2, 2, 2-trichloropropanol.
4. Chloroform.

4. In Cannizzaro reaction given below:

$2\text{PhCHO}\xrightarrow{\stackrel{-}{\hbox{ OH}}}\text{PhCH}_2+\text{OH}+\text{PhCO}_2^-$ the slowest step is:

1. The attack ^-OH at the carboxyl group.
2. The transfer of hydride to the carbonyl group.
3. The abstraction of proton from the carboxylic group.
4. The deprotonation of PhCH₂OH.

5. Which of the following reaction will not result in the formation of carbon-carbon bonds?

1. Cannizzaro reaction.
2. Wurtz reaction.
3. Reimer-Tiemann reaction.
4. Friedel-Crafts' acylation.