In keto-enol tautomerism of dicarbonyl compounds, the enol-form is preferred in contrast to the keto-form, this is due to
presence of carbonyl group on each side of -CH2 group
resonance stabilisation of enol form
presence of methylene group
rapid chemical exchange
In the cannizzaro reaction given below, the slowest step is
2Ph - CHO Ph - CH2 - OH + PhCO
the attack of OH- at the carbonyl group
the transfer of hydride ion to the carbonyl group
the abstraction of a proton from the carboxylic acid
the deprotonation of Ph - CH2OH
Which of the following pairs give positive Tollen's test?
Glucose, sucrose
Glucose, fructose
Hexanal, acetophenone
Fructose, sucrose
Which of the following isomerism is shown by ethyl acetoacetate?
Geometrical isomerism
Keto-enol tautomerism
Enantiomerism
Diastereoisomerism
Ketones [R - - R'] where, R = R' = alkyl group can be obtained in one step by
hydrolysis of esters
oxidation of primary alcohols
oxidation of secondary alcohols
reaction of acid halide with alcohols
An optically active compound 'X' has molecular formula C4H8O3. It evolves CO2 with aqueous NaHCO3. 'X' reacts with LiAlH4 to give an achiral compound. 'X' is
CH3CH2C(OH)HCOOH
CH3C(OMe)HCOOH
CH3CH(CH2OH)HCOOH
CH3C(OH)HCH2COOH
Out of H2S2O3, H2S2O4, H2SO5 and H2S2O8 peroxy acids are
H2S2O3; H2S2O8
H2SO5; H2S2O8
H2S2O4; H2SO5
H2S2O3; H2S2O4
In a Claisen condensation reaction (when an ester is treated with a strong base)
a proton is removed from the α-carbon to form a resonance stabilised carbanion of the ester
carbanion acts as a nucleophile in a nucelophilic acyl substitution reaction with another ester molecule
a new C - C bond is formed
All of the above statements are correct
An organic compound B is formed by the reaction of ethyl magnesium iodide with a substance A, followed by treatment with dilute aqueous acid. Compound B does not react with PCC or PDC in dichloromethane. Which of the following is a possible compound for A?
CH3CH2COCH3
CH3COH
H2C=O