Aldehydes and ketones contain which functional group
A –COOH
B –CHO
C >C=O
D –OH
Both aldehydes and ketones contain the carbonyl group.
Aldehydes differ from ketones because aldehydes have
A two alkyl groups
B one hydrogen attached to carbonyl carbon
C aromatic ring
D two hydrogen atoms
Aldehydes have at least one hydrogen on the carbonyl carbon.
Which compound is an aldehyde
A acetone
B acetophenone
C formaldehyde
D benzophenone
Formaldehyde (HCHO) is the simplest aldehyde.
Carbonyl carbon in aldehydes and ketones is
A sp³ hybridised
B sp hybridised
C sp² hybridised
D dsp² hybridised
Carbonyl carbon has trigonal planar geometry.
Aldehydes and ketones undergo mainly
A electrophilic substitution
B nucleophilic substitution
C nucleophilic addition
D free radical substitution
Polar C=O bond attracts nucleophiles.
Which factor increases nucleophilic addition rate
A electron-donating groups
B electron-withdrawing groups
C bulky substituents
D steric hindrance
They increase electrophilicity of carbonyl carbon.
Aldehydes are more reactive than ketones due to
A steric hindrance
B inductive effect
C less steric hindrance and greater electrophilicity
D resonance
Two alkyl groups in ketones reduce reactivity.
Order of reactivity towards nucleophilic addition is
A ketone > aldehyde > formaldehyde
B aldehyde > ketone > formaldehyde
C formaldehyde > aldehyde > ketone
D formaldehyde > ketone > aldehyde
Formaldehyde has least steric hindrance.
Addition of HCN to aldehydes gives
A alcohol
B nitrile
C cyanohydrin
D amide
CN⁻ adds to carbonyl carbon.
Formation of cyanohydrin involves attack of
A H⁺
B CN⁻
C NH₃
D OH⁻
CN⁻ acts as nucleophile.
Which reagent distinguishes aldehydes from ketones
A Fehling’s solution
B NaBH₄
C Grignard reagent
D HCN
Aldehydes reduce Fehling’s solution.
Tollen’s reagent gives silver mirror with
A ketones
B aldehydes
C alcohols
D acids
Aldehydes reduce Ag⁺ to Ag.
Which aldehyde does not respond to Fehling’s test
A acetaldehyde
B formaldehyde
C benzaldehyde
D propanal
Aromatic aldehydes do not reduce Fehling’s solution.
Schiff’s reagent gives pink colour with
A ketones
B aldehydes
C acids
D esters
Aldehydes restore colour.
Which compound gives iodoform test
A formaldehyde
B acetaldehyde
C benzaldehyde
D acetone
Compounds containing –COCH₃ group give iodoform test.
Reduction of aldehydes with NaBH₄ gives
A acids
B ketones
C primary alcohols
D secondary alcohols
Aldehydes reduce to primary alcohols.
Reduction of ketones gives
A primary alcohol
B secondary alcohol
C tertiary alcohol
D alkane
Carbonyl group is reduced to –OH.
Oxidation of aldehydes gives
A alcohols
B ketones
C acids
D esters
Aldehydes are easily oxidised.
Ketones do not oxidise easily because
A lack of oxygen
B lack of α-hydrogen
C strong C–C bond
D require C–C bond cleavage
Oxidation would break carbon skeleton.
Which reagent oxidises aldehyde selectively
A KMnO₄
B Tollens’ reagent
C NaBH₄
D LiAlH₄
Mild oxidising agent.
Aldol condensation occurs in compounds having
A no α-hydrogen
B α-hydrogen
C aromatic ring
D halogen
Enolate formation requires α-hydrogen.
Initial product of aldol condensation is
A α,β-unsaturated aldehyde
B β-hydroxy aldehyde
C ketone
D ester
Aldol product forms first.
Cannizzaro reaction is shown by aldehydes
A having α-hydrogen
B without α-hydrogen
C aromatic ketones
D all aldehydes
Disproportionation occurs.
Cannizzaro reaction produces
A two alcohols
B two acids
C alcohol and acid
D ester
One molecule reduced, other oxidised.
Cross Cannizzaro reaction requires
A two aldehydes without α-hydrogen
B one aldehyde with α-hydrogen
C two ketones
D alcohol
Prevents self-disproportionation.
Grignard reagent adds to carbonyl compounds to form
A alkane
B alcohol
C acid
D ester
After hydrolysis, alcohol is formed.
Reaction of formaldehyde with Grignard reagent gives
A secondary alcohol
B tertiary alcohol
C primary alcohol
D ketone
One alkyl group is added.
Reaction of ketone with Grignard reagent gives
A primary alcohol
B secondary alcohol
C tertiary alcohol
D aldehyde
Two alkyl groups already present.
Carboxylic acids contain which functional group
A –CHO
B –CO–
C –COOH
D –OH
Carboxyl group is present.
Carboxylic acids are acidic due to
A inductive effect
B resonance stabilisation of carboxylate ion
C hydrogen bonding
D steric effect
Negative charge is delocalised.
Which acid is strongest
A formic acid
B acetic acid
C propionic acid
D butyric acid
No +I effect.
Electron-withdrawing groups increase acidity by
A destabilising carboxylate ion
B stabilising carboxylate ion
C increasing steric hindrance
D decreasing polarity
−I effect stabilises negative charge.
Reaction of carboxylic acid with alcohol gives
A ether
B ester
C aldehyde
D ketone
Esterification reaction.
Esterification is catalysed by
A NaOH
B HCl
C conc. H₂SO₄
D NH₃
Acts as catalyst and dehydrating agent.
Reduction of carboxylic acid with LiAlH₄ gives
A aldehyde
B ketone
C primary alcohol
D secondary alcohol
Strong reducing agent.
Decarboxylation removes
A CO
B CO₂
C H₂O
D O₂
Loss of carbon dioxide.
Heating sodium salt of acid with soda lime gives
A alkene
B alcohol
C alkane
D aldehyde
One carbon less.
Which compound does not give Cannizzaro reaction
A formaldehyde
B benzaldehyde
C acetaldehyde
D chloral
Has α-hydrogen.
Acid chloride is more reactive than acid because
A resonance
B inductive effect
C poor leaving group in acid
D steric hindrance
Cl⁻ is better leaving group than OH⁻.
Acyl substitution involves
A nucleophilic addition only
B electrophilic substitution
C nucleophilic addition–elimination
D free radical
Common in acid derivatives.
Carboxylic acids show nucleophilic substitution because
A C=O is polar
B –OH is good leaving group
C acid forms acylium ion
D resonance destabilisation
Nucleophile attacks carbonyl carbon.
Acid chloride reacts fastest with nucleophile because
A steric hindrance
B poor leaving group
C strong −I effect of Cl
D weak C–Cl bond
Increases electrophilicity.
Which reagent converts acid to acid chloride
A NaOH
B SOCl₂
C NH₃
D NaBH₄
Thionyl chloride.
Which compound gives effervescence with NaHCO₃
A alcohol
B phenol
C carboxylic acid
D aldehyde
CO₂ gas is released.
Which compound is most acidic
A phenol
B ethanol
C acetic acid
D water
Carboxylic acids are strongest.
Which acid shows strongest −I effect
A acetic acid
B chloroacetic acid
C formic acid
D propionic acid
Chlorine withdraws electrons.
Reduction of acid chloride with Rosenmund catalyst gives
A acid
B alcohol
C aldehyde
D ketone
Poisoned Pd catalyst.
Which reaction converts nitrile to aldehyde
A Stephen reaction
B Cannizzaro reaction
C Aldol reaction
D Perkin reaction
Reduction followed by hydrolysis.
Which compound shows both aldol and Cannizzaro reactions
A acetaldehyde
B formaldehyde
C benzaldehyde
D no compound
Aldol needs α-H; Cannizzaro requires no α-H.
Correct statement is
A Ketones are more reactive than aldehydes
B Aldehydes resist oxidation
C Carboxylic acids are stronger acids than phenols
D Aldol reaction occurs without base
Due to resonance stabilisation of carboxylate ion.