हिंदी
कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

Give plausible explanation for the following: Cyclohexanone forms cyanohydrin in good yield but 2, 2, 6 trimethylcyclohexanone does not.

Advertisements
Advertisements

प्रश्न

Give plausible explanation for the following:

Cyclohexanone forms cyanohydrin in good yield but 2, 2, 6 trimethylcyclohexanone does not.

रासायनिक समीकरण/संरचनाएँ
कारण बताइए
Advertisements

उत्तर

Due to the presence of three methyl groups at α-places, nucleophilic attack of CN– ions does not occur. This steric hindrance is absent in cyclohexane. Hence, nucleophilic attack of CN– ions occurs quickly. Hence, cyclohexanone cyanohydrin is obtained in good yield.

shaalaa.com
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 8: Aldehydes, Ketones and Carboxylic Acids - Exercises [पृष्ठ २५७]

APPEARS IN

एनसीईआरटी Chemistry Part 1 and 2 [English] Class 12
अध्याय 8 Aldehydes, Ketones and Carboxylic Acids
Exercises | Q 8.18 (i) | पृष्ठ २५७

संबंधित प्रश्न

How are the following compounds prepared?

benzaldehyde from benzene


Predict the product of the following reaction:


What is meant by the following term? Give an example of the reaction in the following case.

Acetal


How will you bring about the following conversion in not more than two steps?

Bromobenzene to 1-Phenylethanol


Complete the synthesis by giving missing starting material, reagent or product.


Write balanced chemical equations for action of ammonia on - acetaldehyde


Write balanced chemical equations for action of ammonia on - acetone


How will you convert sodium acetate to methane?


Write the main product formed when propanal reacts with the following reagents: 
2 moles of 3 CH OH in presence of dry HCl 


A Idol condensation will not be observed in


Acetaldehyde and acetone differ in their reaction with


In the following reaction

\[\ce{Carbonyl compound + MeOH <=>[HCl] acetal}\]

Rate of the reaction is the highest for ______.


The following questions are case-based questions. Read the passage carefully and answer the questions that follow:

The carbon-oxygen double bond is polarised in aldehydes and ketones due to higher electronegativity of oxygen relative to carbon. Therefore, they undergo nucleophilic addition reactions with a number of nucleophiles such as HCN, NaHSO3, alcohols, ammonia derivatives and Grignard reagents. Aldehydes are easily oxidised by mild oxidising agents as compared to ketones. The carbonyl group of carboxylic acid does not give reactions of aldehydes and ketones. Carboxylic acids are considerably more acidic than alcohols and most of simple phenols.

Answer the following:

(a) Write the name of the product when an aldehyde reacts with excess alcohol in the presence of dry HCl. (1)

(b) Why carboxylic acid is a stronger acid than phenol? (1)

(c) (i) Arrange the following compounds in increasing order of their reactivity towards CH3MgBr: (1)

CH3CHO, \[\begin{array}{cc}
\ce{(CH3)3C-C-CH3}\\
\phantom{....}||\\
\phantom{....}\ce{O}
\end{array}\],  \[\begin{array}{cc}
\ce{CH3-C-CH3}\\
||\\
\ce{O}
\end{array}\]

(ii) Write a chemical test to distinguish between propanal and propanone. (1)

OR

(c) Write the main product in the following: (2)

(i)
(ii)

Draw the structure of the following derivative.

The ethylene ketal of hexane-3-one


Draw the structure of the following derivative.

Acetaldehydedimethylacetal


Draw the structure of the following derivative.

The ethylene ketal of hexan-3-one


Draw structure of the following derivative.

The ethylene ketal of hexan-3-one


Draw structure of the following derivative.

The ethylene ketal of hexan-3-one


Draw the structure of the given derivative.

The ethylene ketal of hexan-3-one


Give an example of the reaction in the following case.

Oxime


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×