Answer
405.3k+ views
Hint: To answer this question, you should recall the concept of Cannizzaro reaction. Cannizzaro reaction is a chemical reaction that involves the base-induced disproportionation of two molecules. It occurs when alpha hydrogen is missing in a carbonyl compound. It forms an alcohol and an acid.
Complete Step by step solution:
The reactants involved are non-enolizable aldehyde to yield a carboxylic acid and a primary alcohol. The reaction is initiated by a nucleophilic acyl substitution on a non-enolizable aldehyde where the leaving group attacks another aldehyde. This results in an intermediate which is tetrahedral in geometry from the attack of hydroxide on a carbonyl.
Now, a proton is exchanged by acid and alkoxide ions. With the introduction of a base of high concentration, the aldehyde forms an anion which has a charge of two. After this step a hydride ion is transferred to a second molecule of the aldehyde, forming carboxylate and alkoxide ions.
The overall mechanism can be summarised by the following mechanism:
In the reaction, the reactant i.e. glyoxal does not have any alpha hydrogen so it will perform intramolecular Cannizzaro reaction. This means that one of the aldehydes will reduce and the other will oxidise.
Hence, the correct option is C.
The overall mechanism has been summarised as below:
Additional information: Another important reaction of aldehydes is aldol condensation. The reaction of aldehydes and ketones containing at least one $\alpha $ hydrogen is treated with dilute alkali; they form $\beta $ - hydroxy aldehydes or $\beta $ - hydroxy ketones (ketol) respectively. We know that in aldol condensation the hydroxide ion functions as a base moving the acidic hydrogen-producing the reactive enolate ion. Further, the aldehyde is attacked at the electrophilic carbonyl carbon by the nucleophilic enolate ion resulting in an alkoxide intermediate. The alkoxide ion now formed deprotonates the water molecule, ultimately resulting in hydroxide and the $\beta $ – hydroxy aldehyde.
Note: Acetaldehyde does not participate in Cannizzaro reaction because the alpha-hydrogens are deprotonated due to the alkaline environment. Since acetaldehyde contains three alpha hydrogen, it readily enolate ions upon deprotonation and therefore cannot participate in the reaction.
Complete Step by step solution:
The reactants involved are non-enolizable aldehyde to yield a carboxylic acid and a primary alcohol. The reaction is initiated by a nucleophilic acyl substitution on a non-enolizable aldehyde where the leaving group attacks another aldehyde. This results in an intermediate which is tetrahedral in geometry from the attack of hydroxide on a carbonyl.
Now, a proton is exchanged by acid and alkoxide ions. With the introduction of a base of high concentration, the aldehyde forms an anion which has a charge of two. After this step a hydride ion is transferred to a second molecule of the aldehyde, forming carboxylate and alkoxide ions.
The overall mechanism can be summarised by the following mechanism:
![seo images](https://www.vedantu.com/question-sets/0c95835e-9764-4652-b893-b8ab2fe9ac1b8236995132540270094.png)
In the reaction, the reactant i.e. glyoxal does not have any alpha hydrogen so it will perform intramolecular Cannizzaro reaction. This means that one of the aldehydes will reduce and the other will oxidise.
Hence, the correct option is C.
The overall mechanism has been summarised as below:
![seo images](https://www.vedantu.com/question-sets/91835b89-fc78-4f2e-bf4a-9e5d658376094943952705539464609.png)
Additional information: Another important reaction of aldehydes is aldol condensation. The reaction of aldehydes and ketones containing at least one $\alpha $ hydrogen is treated with dilute alkali; they form $\beta $ - hydroxy aldehydes or $\beta $ - hydroxy ketones (ketol) respectively. We know that in aldol condensation the hydroxide ion functions as a base moving the acidic hydrogen-producing the reactive enolate ion. Further, the aldehyde is attacked at the electrophilic carbonyl carbon by the nucleophilic enolate ion resulting in an alkoxide intermediate. The alkoxide ion now formed deprotonates the water molecule, ultimately resulting in hydroxide and the $\beta $ – hydroxy aldehyde.
Note: Acetaldehyde does not participate in Cannizzaro reaction because the alpha-hydrogens are deprotonated due to the alkaline environment. Since acetaldehyde contains three alpha hydrogen, it readily enolate ions upon deprotonation and therefore cannot participate in the reaction.
Recently Updated Pages
How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Why Are Noble Gases NonReactive class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let X and Y be the sets of all positive divisors of class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x and y be 2 real numbers which satisfy the equations class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x 4log 2sqrt 9k 1 + 7 and y dfrac132log 2sqrt5 class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x22ax+b20 and x22bx+a20 be two equations Then the class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
At which age domestication of animals started A Neolithic class 11 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Which are the Top 10 Largest Countries of the World?
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give 10 examples for herbs , shrubs , climbers , creepers
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference Between Plant Cell and Animal Cell
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write a letter to the principal requesting him to grant class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Change the following sentences into negative and interrogative class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill in the blanks A 1 lakh ten thousand B 1 million class 9 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)