ECAT Pre Engineering Chemistry Chapter 23 MCQ Test With Answer

Which reagent will distinguish a ketone from an aldehyde

• Br₂ A
• 2, 4-dinitrophenylhydrazine B
• NaBH₄ C
• Tollen's reagent D

In Tolten's best, the end product is ______ formed

• White ppts A
• Red ppts B
• Yellow ppts C
• Silver mirror D

Carboxyl compounds have functional group:

• R-C-X A
• R-CH=O B
• RCOR C
• All D

Which of the following reactions is used for detecting presence of carbonyl group?

• Reaction with hydroxylamine A
• Reaction with hydrazine B
• Reaction with phenyl hydrazine C
• All D

Which isomer of C₅H₁₁OH gives, one dehydration, the greastest number of different alkenes

• 
  A
• 
  B
• 
  C
• 
  D

C₂H₅CHO and (CH₃)₂CO can be distunguished by testing with

• Phenyl hydrazine A
• Hydroxylamine B
• Fehling solution C
• Sodium bisulphate D

Formalin is an aqueous solution of

• Furfural A
• Fluorescein B
• Formaldehyde C
• Formic acid D

Which of the following will have the highest boiling point?

• Methanal A
• Ethanal B
• Propanal C
• 2-Hexanone D

An organic compound has the following properties ; It gives a positive tri-iodomethane test; it gives a yellow ppt, with 2, 4-DNP regent; it does not react with Tollen's reagent . Which compound would give these results

• CH₃CHO A
• CH₃CH₂OH B
• CH₃CH₂COCH₃ C
• CH₃CH₂CH₂CHO D

Which one of the following statement is wrong regarding differences between aldehydes and ketones

• Aldehydes undergo reduction to form primary alcohols while ketones undergo reduction to form secondary alcohols A
• Aldehydes undergo oxidation to form acids having less number of carbon atoms while ketones undergo oxidation to form acids having same number of carbon atoms B
• Aldehydes give positive silver mirror test while ketones give negative -mirror test C
• Aldehydes can undergo polymerization while ketones cannot undergo polymerizarion D

A food chemist wants to create the odour of pineapples for a product. An ester with this odour has the formula C₃H₇COOC₂H_5.Which pair of reagents would produce this ester

• C₂H₅CI and C₃H₇COOH A
• C₂H₅OH and C₃H₇CONH₂ B
• C₂H₅OH and C₃H₇COOH C
• C₃H₇OH and C₂H₅COCI D

Propyne on hydrolysis in presence of H₂SO₄and HgSO₄gives

• Acetaldehyde A
• Acetone B
• Formaldehyde C
• None D

The addition of HCN to carbonyl compounds is an example of

• Nucleopihlic substituion A
• Electrophilic addition B
• Nueleophilic addition C
• Electrophilic substitution D

Which is mild oxidizing agent ?

• Tollen's reagent A
• KMnO₄ / H₂SO₄ B
• K₂Cr₂O₇ / H₂SO₄ C
• HNO₃ D

The product of the reaction between propanone and HCN is hydrolysed under acidic conditions. What is the formula of the final product

• CH₃CH(OH)COOH A
• CH₃CH₂CH(OH)COOH B
• (CH₃)₂C(OH)COOH C
• CH₃CH₂CH₂COOH D

Tollen's reagent is

• Ammonical cuprous chloride A
• Ammonical cuprous oxide B
• Ammonical silver bromide C
• Ammonical silver nitrate D

Formaldehyde is used to make

• Plastics A
• Medicine B
• Antiseptic C
• All of these D

Aldehydes and ketones are carbonyl compounds. Which of them react both with NaBH₄and with Tollen's reagent

• Both aldehydes and ketones A
• Aldehydes only B
• Ketones only C
• Neither aldehydes nor ketones D

• Q and R Q and R A
• R only Q and R B
• Q and R R only C
• Q only R only D

Aldehydes are reduced to :

• Pri-alcohol A
• Sec-alcohol B
• Ter-alcohol C
• All of these D

• Br_2(aq) A
• 2, 4-dinitrophenylhydrazine B
• NaBH C
• Tollen's reagent D

Ketones are prepared by the oxidation of:

• Primary alcohol A
• Secondary alcohol B
• Tertiary alcohol C
• None of these D

Reduction of aldehydes with HI and P gives

• Primary alcohols A
• Secondary alcohols B
• Alkanes C
• Tertiary alcohols D

Aldehyde and small methyl ketones form crystalline ______ ppts with saturated sodium bisulphate solution

• White A
• Red B
• Yellow C
• None of these D

The color of ppts formed by Benedirct's test is

• Brick red A
• Wine red B
• Yellow C
• Orange D

Aldehydes are produce in atmosphere by

• Oxidation of secondary alcohols A
• Reduction of alkenes B
• Reaction of oxygen atoms with hydrocarbons C
• Reaction of oxygen atoms with ozone D

During the mechanism of aldol condensation a/an ______ is formed

• Oxide A
• Alkali B
• Alkoxide ion C
• None of these D

Cannizzzaro's reaction is not given by:

• Formaldehyde A
• Acetaldehyde B
• Benzaldehyde C
• Trimethyl D

Cannizzaro reaction is not given by

• Trimethyl acetaldehyde A
• Acetaldehyde B
• Benzaldehyde C
• Formaldehyde D

Ethanal may be converted into a three-carbon acid in a two-step process.

Which compound is the intermediate

• CH₃CO₂H A
• CH₃CN B
• CH₃CH₂CN C
• CH₃CH(OH)CN D