Base catalysed aldol condensation occurs with :
Aldehydes having at least one α-hydrogen atom undergo aldol condensation.
Which of the following compounds will give a yellow precipitate with iodine and alkali?
Iodoform reaction is given by the compounds containing
CH3CHO and CH3CH2OH.2-Hydroxypropane (CH3CHOHCH3) contains the grouping CH3CHOH— and acetophenone (C6H5COCH3) contains the grouping CH3CO– linked to carbon and hence give yellow ppt. with I2 and alkali—iodoform test.
In methyl acetate (CH3COOC2H5) and acetamide (CH3CO–NH2), CH3CO is attached to a hetero atom but not to carbon atom and hence both these compounds do not give iodoform test.
Which of the following compounds will react with ethanolic KCN?
Ethyl chloride and acetyl chloride react with alc. KCN by nucleophilic substitution reaction while benzaldehyde undergoes benzoin condensation :
Keto-enol tautomerism is observed in
Keto-enol tautomer ism is sh own in compounds having a-hydrogen on the C adjacent to the CO group.
Which of the following are examples of aldol condensation?
NOTE : Aldehydes and ketones containing a-Hydrogen atom undergo aldol condensation.
A new carbon-carbon bond formation is possible in
Which of the following will react with water?
Three Cl of chloral makes its carbonyl carbon highly electron deficient, hence H2O, a nucleophile easily adds on it forming chloral hydrate, CCl3CH(OH)2, which is quite stable due to intramolecular H–bonding between two –OH groups.
Which of the following will undergo aldol condensation?
Carbonyl compounds having α – H or α - D undergo aldol condensation.
Which of the following reactants on reaction with conc. NaOH followed by acidification gives following lactone as the product?
The major products P and Q are
The smallest ketone and its next homologue are reacted with NH2OH to form oxime
Identify the binary mixture(s) that can be separated into individual compounds, by differential extraction as shown in the given scheme.
(A) Both are soluble in NaOH, hence inseparable.
(B) Only benzoic acid (C6H5COOH) is soluble in NaOH and NaHCO3, while benzyl alcohol (C6H5CH2OH) is not.
(C) Although NaOH can enable separation between benzyl alcohol (C6H5CH2OH) and phenol (C6H5OH) as only the later is soluble in NaOH. However, in NaHCO3, both are insoluble. Hence, inseparable.
(D) a-Phenylacetic acid (C6H5CH2COOH) is soluble in NaOH and NaHCO3. While benzyl alcohol (C6H5CH2OH) is not. Hence, separable.
With reference to the scheme given below, which of the given statement(s) about T, U, V and W is (are) correct ?
In the following reaction, the product(s) formed is(are)
After completion of the reactions (I and II), the organic compound(s) in the reaction mixtures is(are)
The major product of the following reaction is
Positive Tollen’s test is observed for
Aldehydes and a-Hydroxyketones show positive Tollen's test.
The correct statement(s) about the following reaction sequence is(are)
Q is steam volatile not R.
Q and R show positive test with 1% aqueous FeCl3 solution.
Q, R, S give yellow precipitate with 2, 4-dinitrophenyl hydrazine.
Reagent(s) which can be used to bring about the following transformation is (are)
LiAlH4/(C2H5)2O : Reduces to ester s, carboxylic acid, epoxides and aldehydes and ketones.
BH3 in T.H.F : Reduces to –COOH and aldeh ydes into alcohols but do not reduce to esters and epoxides.
NaBH4 in C2H5OH : Reduces only aldehydes and ketones into alcohols but not to others.
Raney Ni in T.H.F. : Do not reduce to –COOH, –COOR and epoxide but it can reduce aldehyde into alcohols.