Advertisements
Advertisements
प्रश्न
What is meant by the following term? Give an example of the reaction in the following case.
Semicarbazone
Advertisements
उत्तर
Semicarbazones are derivatives of aldehydes and ketones produced by the condensation reaction between a ketone or aldehyde and semicarbazide.
APPEARS IN
संबंधित प्रश्न
Give plausible explanation for the following:
There are two −NH2 groups in semicarbazide. However, only one is involved in the formation of semicarbazones.
Write balanced chemical equations for action of ammonia on - acetone
Write the main product formed when propanal reacts with the following reagents:
2 moles of 3 CH OH in presence of dry HCl
Acetone, Acetaldehyde, Benzaldehyde, Acetophenone – reactivity towards addition of HCN.
Which of the following is the correct representation for intermediate of nucleophilic addition reaction to the given carbonyl compound (A):
(i) 
(ii) 
(iii) 
(iv) 
Write a test to differentiate between pentan-2-one and pentan-3-one.
The pH of blood does not appreciably change by a small addition of acid or base because
Grignard reagent on reaction with acetone forms.
Write the name of product formed, when acetone is treated with 2, 4-dinitrophenyl hydrazine.
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 structure of the following derivative.
The ethylene ketal of hexane-3-one
Draw structure of the following derivative.
Acetaldehydedimethylacetal
Draw structures of the following derivative.
The ethylene ketal of hexan-3-one
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
Which of the following will not be formed when calcium formate is distilled with calcium acetate?
