Free Fundamental Principles of Organic Chemistry MCQs with Answers

• A. Cl
• B. N2
• C. CO2
• D. CO

Explanation: The Beilstein test detects halogens in an organic compound by producing a volatile copper halide that gives a coloured flame.

• A. ethylene glycol
• B. glycerol
• C. picric acid
• D. ethyl acetate

Explanation: Ethyl acetate, CH3COOCH2CH3, is an ester and contains no hydroxyl, or -OH, group.

• A. CH3NH2
• B. CH3NO2
• C. CH3CN
• D. CH2 = CH - CN

Explanation: Methyl cyanide is acetonitrile, whose condensed formula is CH3CN; the -CN group is the nitrile functional group.

• A. CH2Cl2
• B. CH3Cl
• C. CHCl3
• D. CCl4

Explanation: Chloroform is trichloromethane, so three hydrogen atoms of methane are replaced by chlorine and its formula is CHCl3.

• A. Grignard reagent
• B. Metallic alkyl halide
• C. Both A & B
• D. Alkyl

Explanation: R-Mg-Br is an organomagnesium halide called a Grignard reagent, and it contains an alkyl group directly bonded to a metal, so it is also…

• A. Imino group
• B. Amino group
• C. Amide group
• D. Nitro group

Explanation: Aniline is aminobenzene, with an -NH2 group directly attached to the benzene ring, so it contains an amino group.

• A. Hydrogen
• B. Oxygen
• C. Sulphur
• D. OH

Explanation: Benzene sulphonic acid has the structure C6H5SO3H, so the benzene carbon is directly bonded to the sulphur atom of the sulphonic group.

• A. radical
• B. hydrocarbon
• C. functional group
• D. ion

Explanation: A functional group is a specific atom or group of atoms that gives an organic compound its characteristic chemical reactions and…

• A. OH
• B. R-CO-R
• C. R-O-R
• D. R-COOH

Explanation: An ether contains an oxygen atom single-bonded to two carbon-containing groups, represented generally as R-O-R.

• A. R-NH2
• B. RCONH2
• C. R - NH - R
• D. C6H5NH2

Explanation: An amide contains a carbonyl group directly attached to nitrogen, represented by RCONH2.

• A. chain Isomerism
• B. Functional Group Isomerism
• C. Metamerism
• D. Position Isomerism

Explanation: Aldehydes and ketones can have the same molecular formula but different functional groups, such as propanal and propanone, so they show…

• A. 2
• B. 4
• C. 7
• D. 16

Explanation: An aldohexose has four chiral carbon atoms, so the number of possible stereoisomeric aldoses is 2^4 = 16.

• A. aldehydes
• B. ketones
• C. alcohols
• D. carboxylic acid

Explanation: Ethers and alcohols can have the same molecular formula but different functional groups, so they show functional-group isomerism.

• A. metamerism
• B. functional group isomerism
• C. geometric isomerism
• D. position isomerism

Explanation: 1-propanol and 2-propanol have the same molecular formula and the same alcohol functional group, but the OH group is attached at different…

• A. Boiling point
• B. Melting point
• C. Percentage composition
• D. Structural formula

Explanation: Pentane and 2-methylbutane are structural isomers with the same molecular formula, C5H12, so they have the same elemental percentage…

• A. cis-trans isomerism
• B. geometric isomerism
• C. both a & b
• D. none of the above

Explanation: Propene has the structure CH3-CH=CH2; the terminal double-bonded carbon has two identical hydrogen atoms, so cis-trans or geometric…

• A. one
• B. two
• C. three
• D. four

Explanation: C5H12 has three structural isomers: n-pentane, 2-methylbutane and 2,2-dimethylpropane.

• A. polymer
• B. monomer
• C. isomer
• D. allotropes

Explanation: Isomers have the same molecular formula but different arrangements of atoms or different spatial arrangements.

• A. Alkanes
• B. Alkenes
• C. Alkynes
• D. Esters

Explanation: Geometric isomerism is common in alkenes because the pi bond prevents free rotation and each double-bonded carbon may carry two different…

• A. 2
• B. 3
• C. 4
• D. 5

Explanation: The formula C4H9Cl has four structural isomers: 1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane and 2-chloro-2-methylpropane.