1. Which of the following is the simplest member of organic compounds?
a) Formic acid
Explanation: Methane is the simplest member of the alkane family and indeed the simplest of organic compounds, as all other compounds are derived by altering this compound.
2. Hydrocarbons are organic compounds with element __________
a) Both hydrogen and carbon
Explanation: These organic compounds are made up of only carbon and hydrogen and hence the name hydrocarbons.
3. If a bond is made up of a large number of organic compounds, then the bond is termed as?
a) Metallic bond
b) Dipolar bond
c) Ionic bond
d) Covalent bond
Explanation: This is because they have the tendency to transfer electrons.
4. Organic compounds are broadly classified as _________
a) alicyclic compounds and acyclic compounds
b) Cyclic compounds and alicyclic compounds
c) Open chain compounds and acyclic compounds
d) Open chain compounds and linear chain compounds
Explanation: Organic compounds are broadly classified into open chain and closed chain compounds.
5. Which of the following is not a class of organic compound?
b) Electro compounds
c) Nitro compound
d) Carbonyl compound
Explanation: Classes of organic compounds are those which involves organic compounds such as carbon, hydrogen and oxygen. Hence, electro compounds is not a class of organic compounds.
6. Which of the following chemical bond were described by Kossel and Lewis?
a) Ionic and Covalent bond
b) Coordinate bond
c) Metallic bond
d) Polar covalent bond
Explanation: Both Ionic and Covalent bond arise from the tendency of atoms to attain a stable configuration of electrons.
7. Organic compounds can be classified even based upon the function groups. Identify the one which is not a functional group?
Explanation: Isocyanide is a compound and it is not a functional group.
8. Identify the one which does not come under the organic addition reaction?
Explanation: Dehydration comes under elimination reaction and hence it does not come under addition reaction.
9. Which of the following organic compound with molecular formula C3H C12 exhibits only one signal in the IH NMR spectrum?
a) 1, 2-dichloropropane
b) 1, 1-dichloropropane
c) 2, 2-dichloropropane
d) 1, 3-dichloropropane
Explanation: Only (a) compound has all chemically equivalent hydrogen. So, give only one peak.
10. Which of the following has zero dipole moment?
Explanation: The ring of benzene is completely closed and is of perfect stability and hence it has zero dipole moment.
Explanation: In compound a;
Here only 2 types of Hydrogen are present (two Ha & twelve Hb). So, 2 singlets only. There is no need to check 13C NMR. Still, if you check three types carbon are present (two C1, four C2 and four C2 carbon). Hence, there peak for 13C NMR.
12. An organic compound (MF; C8H10O) exhibited the following 1H NMR special data: 62.5 (3H, s), 3.8 (314, s), 6.8 (2H, d, J 8 Hz), 7.2 (2H, d, J 8 Hz) ppm. What will be the compound among the choices?
a) 4-methylbenzyl alcohol
b) 4-methyl anisole
3Ha –> 3.8, singlet (deshielded because of –I of oxygen)
3Hb –> 2.5, singlet (No such –I)
2Hc –> 7.2, doublet (deshielded because of anisotropy effect of benzene as well as because of –I of oxygen)
2Hd –> 6.8, doublet (deshielded because of anisotropy of benzene).
13. Which of the following complex is in which organic ligand is having only bond with metal?
Explanation: CH3 is the only σ-donor ligand while C2H4, C5H5, C6H6 are π-acceptor ligands.
14. Which of the following statement is not true about ethers?
a) Lower ethers also act as anaesthetics
b) Simple ethers (such as diethyl ether) are tasteless
c) The lower ethers are highly volatile and flammable
d) Ethers are not organic solvents
Explanation: Because like dissolve like, Diethyl ether is very non-polar compared to water so it will dissolve the non-polar substances and precipitate the ionic compounds. Since like dissolves like, your barely-polar organic ether is often happy to dissolve your non-polar organic molecules.
15. An organic compound A reacts with sodium metal and forms B. On heating with conc. H2SO4, A gives diethyl ether. What are A and B?
a) C4H9OH and C4H9ONa
b) CH3OH and CH3ONa
c) C2H5OH and C2H5ONa
d) C3H7OH and CH3ONa
Explanation: When C2H5OH reacts with sodium metal and forms C2H5ONa and on heating with H2SO4 giver diethyl ether.
16. An organic compound Q exhibited the following spectral data obtained by mass spectroscopy.
IR: 1760 cm–1
1HNMR: chemical reference (ppm): 7.2 (IH, d, 16.0 Hz), 5.1 (IH, m), 2.1 (3H, s), 1.8 (3H, d, J = 7.0 Hz)
13CNMR chemical reference (ppm): 170 (carbonyl carbon). What is compound Q?
IR: 1760 cm–1
Some options are not possible because of IR data.
1760 cm–1 –> Represent either ester or anhydride
ester –>with cross conjugation or anhydride
chemical reference: 7.2 (1H), d, J = 16.0 Hz
This ‘J’ shows it is a trans alkene.
17. Which Biomolecules simply refers as “Staff of life” in the given macromolecules?
Explanation: Carbohydrates belong to a group of complex biomolecules commonly regarded as the “staff of life.” They are the most abundant organic compounds in living organisms and are among the four major classes of biomolecules. During photosynthesis, carbohydrates are produced from the reaction of carbon dioxide with water. Carbohydrates go by several common names, including sugars, starches, saccharides, and polysaccharides.
Explanation: Di-isobutyl aluminium hydride (DIBAH) is a selective reducing agent. It does not reduce esters to 1° alcohols (lithium aluminium hydride can be used to reduce esters to 1° alcohols).
19 Ethylene glycol on treatment with phosphorus tri-iodide yields
a) ethylene di-iodide
d) ethyl iodide
Explanation: Phosphorus triiodide (PI3) is an unstable red solid which reacts violently with water. It is a common misconception that PI3 is too unstable to be stored; it is, in fact, commercially available. It is widely used in organic chemistry for converting alcohols to alkyl iodides.
20. Which of the following is true about transesterification?
a) exchanging the organic alkyl group of an alcohol with the organic group alkyl of an ester
b) exchanging the organic alkyl group of an ester with the organic group alkyl of an ether
c) exchanging the organic alkyl group of an ester with the organic group alkyl of an alcohol
d) exchanging the organic alkyl group of an ester with the organic group alkyl of an alkane
Explanation: Transesterification is the process of exchanging the organic group R″ of an ester with the organic group R′ of an alcohol.
21. When an organic compound was treated with sodium nitrite and hydrochloric acid in the ice cold, nitrogen gas was evolved copiously. What is the compound?
a) A primary amine
b) A nitrocompound
c) An aromatic primary amine
d) An aliphatic primary amine
Explanation: When an aliphatic primary amine was treated with sodium nitrite and hydrochloric acid in the ice cold, nitrogen gas was evolved.
22. What is the general formula of Diazonium salt?
Explanation: Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group R−N2+X– where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halogen.
23. What is the known name of the reaction given below?
(where, X=Cl, Br, I, OTf; R2=Alkyl, aryl, H; R3=alkyl, aryl)
a) Ullmann reaction
b) Gabriel phthalimide synthesis
c) Buchwald-Hartwig Reaction
d) Chan-Lam coupling
Explanation: The Buchwald–Hartwig amination is a chemical reaction used in organic chemistry for the synthesis of carbon–nitrogen bonds via the palladium-catalyzed cross-coupling of amines with aryl halides.
Explanation: It is also important that products are identified accurately using IUPAC nomenclature: 4,7-Dimethyl-4-heptanol is not an IUPAC name.
25. Which is not a type of catalyst?
b) Homogeneous catalysis
c) Positive catalyst
d) Negative catalyst
Explanation: Homogeneous catalysis is a phenomenon in which the catalyst takes part in the reaction and it is not a type of catalyst.
26. Which among the following is not an example of Acyclic compound?
Explanation: Cyclopropane is a ring (cyclic) compound and hence it does not come with the examples of open chain compounds.
27. Primary alcohols undergo what reaction to form alkenes?
Explanation: Upon elimination or dehydration, the primary alcohols form alkenes.
28. Alkynes cannot be prepared from ___________
a) Other alkynes
Explanation: Only the aldehydes, ketones, and few other alkynes can give rise to a new alkyne compound.
29. Which of the following statement is incorrect about nucleophiles?
a) The nucleophilicity of an element (an electron donor) generally increases on going down a group in the periodic table
b) A nucleophile is electron-deficient species
c) All good nucleophiles are good bases when we deal across the period
d) Nucleophiles have an unshared electron pair and can make use of this to react with an electron deficient species
Explanation: A nucleophile is a chemical species that donates an electron pair to an electrophile to form a chemical bond in relation to a reaction, it is an electron rich species.
30. Who discovered the mass spectrometer?
a) Walter Kaufmann
b) Ernest O. Lawrence
c) Francis Aston
d) J. J Thomson
Explanation: The mass spectrometer was invented by JJ THOMSON. He performed a series of experiments in 1897 designed to study the nature of electric discharge in a high-vacuum cathode-ray tube. Further modified by F. W. Aston shortly after World War I. He constructs the first velocity focusing mass spectrograph which has mass resolving power of 130.
31. What is the wavelength range for UV spectrum of light?
a) 10 nm to 400 nm
b) 0.01 nm to 10 nm
c) 700 nm to 1 mm
d) 400 nm – 700 nm
Explanation: Ultraviolet (UV) is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays (the visible region fall between 380-750 nm and X- rays region fall between 0.01 to 10nm).
32. Which of the following is not considered as an organometallic compound?
a) Grignard reagent
b) Ziese’s salt
Explanation: Cis-platin does not have metal-carbon bond. Therefore, cis platin not considered as organometallic chemistry.
33. What is the concentration of carbon dioxide in the atmosphere?
a) 1.6 x 105 ppm
b) 3.5 x 106 ppm
c) 1.0 x 103 ppm
d) 1.0 x 102 ppm
Explanation: The concentration of carbon dioxide is 3.5 x 106 ppm, that makes it sixth abundant molecule in atmosphere.
34. Which of the following is not an electrophile?
Explanation: The ammonium ion cannot react at the N with a nucleophile because the N already has an octet of electrons.
35. Which of these can be used as moth repellent?
c) Benzene hexachloride
d) Benzal chloride
Explanation: Hexachloroethane can be used as moth repellent. It has also been used as a plasticizer for cellulose esters in place of camphor, a polymer additive, a component of fungicidal and insecticidal formulations, in the formulation of extreme pressure lubricants, and in the manufacture of fire extinguishing fluids.
36. Which alkyl halide has the highest reactivity for a particular alkyl group?
Explanation: Reactivity order for the alkyl halides towards Sn2 reaction is R-I>R-Br>R-Cl>R-F. This can be explained by which halogen atom is a better leaving group compared to the other.
37. Which is not present in Grignard reagent?
a) −COOH group
d) Methyl group
Explanation: Grignard reagents are made from halogenoalkanes (haloalkanes or alkyl halides) and introduces some of their reactions. A Grignard reagent has a formula RMgX where X is a halogen, and R is an alkyl or aryl (based on a benzene ring) group.
38. Reaction of aqueous sodium hydroxide on chlorobenzene gives which of the following products?
c) no reaction
Explanation: Chlorobenzene does not undergo hydrolysis under normal conditions. However, it undergoes hydrolysis when heated in an aqueous sodium hydroxide solution at a temperature of 623 K and a pressure of 300 atm to form phenol.
Explanation: When an aromatic primary amine is treated with nitrous (NaNO2 + HCl) acid at 273 – 278 K, diazonium salts are obtained. Upon warming with water, these diazonium salts finally hydrolyze to phenols.
40. What will be the product for the reaction of catalytic hydrogenation of glycerol?
a) Propylene glycol
b) Ethylene glycol
c) Glycerol carbonate
Explanation: Glycerol is easily reduced to propylene glycol (1,2- dihydroxypropane) with hydrogen at pressures from 10 to 100 atmospheres and temperatures above 150° C. Many catalysts may be used, e.g. Ni, Fe, Pt, Au, Hg, copper chromite or tungstic acid.
Explanation: Silver(I) oxide in aqueous ammonia (“Tollens reagent”) is a mild oxidizing agent which oxidizes aldehydes to carboxylic acids without reacting with carbon-carbon double bonds or many other functional groups.
42. Which of the following is the strongest acid?
Explanation: Presence of -I effect fluorine atom increases the acidic nature by withdrawing electrons.
F−CH2−COOH > Cl−CH2−COOH > Br−CH2−COOH > CH3COOH.
43. Benzoyl chloride is prepared from benzoic acid by which of the following?
a) Cl2, H2O
c) SO2, Cl2
d) Cl2, hv
44. What chemical reaction makes biodiesel?
Explanation: Transesterification chemical reaction makes biodiesel. The most common method of transesterification is the reaction of the ester with an alcohol in the presence of an acid catalyst.
45. Reduction of nitroalkanes yields which compound?
c) Diazo compounds
47. Aniline reacts with acetaldehyde to form which of the following?
a) Diazonium salt
c) Schiff’s base
48. What is the complete IUPAC name of the following substance?
Explanation: The IUPAC name will be (1R,3S)-1-methylcyclopentane-1,3-diol, where 1 position shows R and 3 position shows S.
49. Which element is present as hetero atom in pyridine?
a) Sulphur and nitrogen
Explanation: Pyridine is an analogue of benzene in which one -CH unit is replaced by N. The chemical formula for pyridine is: C5H5N.
50. Which amino acid can form disulphide bonds?
Explanation: Cysteine aminoacid can form disulphide bond(bond which joins two atoms of sulphur atom) because this is the only amino acid with a sulphydryl group in its side chain is cysteine.
51. Which of the following is neither an acid nor base?
Explanation: CH3COOH and CH3OH are organic acids, HCl is strong acid and KCl is a salt.
Chapterwise Multiple Choice Questions on Organic Chemistry
- Organic Compound Basics
- Organic Concepts
- Halogen Containing Organic Compounds
- Oxygen Containing Organic Compounds
- Nitrogen Containing Organic Compounds
- Heterocyclic Compounds
- Polymerisation & Biomolecules
1. MCQ on Organic Compound Basics
The section contains Organic Chemistry multiple choice questions and answers on chemical bond, orbitals, physical properties, isomerism, acids and bases.
2. Organic Chemistry MCQ on Hydrocarbons
The section contains Organic Chemistry questions and answers on hydrocarbons, chlorination, nomenclature, resonance, organic reactions, quantitative analysis, alkanes, alkenes, alkynes, alkadienes and aromatic hydrocarbons.
3. Multiple Choice Questions on Organic Concepts
The section contains Organic Chemistry MCQs on displacement and nucleophilic substitution reactions, organic compound mechanism, elimination reactions, nuclear magnetic resonance, mass, uv – visible and infrared Spectroscopy, redox reactions, organometallic compounds, photochemistry, nucleophiles, electrophiles, bond cleavage, reaction intermediates and kinetics.
4. MCQ on Halogen Containing Organic Compounds
The section contains Organic Chemistry multiple choice questions and answers on alkyl and aryl halides, polyhalogen derivatives, grignard reagent, allyl & vinylic halides.
5. Multiple Choice Questions on Oxygen Containing Organic Compounds
The section contains Organic Chemistry questions and answers on preparation and reactions of alcohols, phenols, ethers, oxiranes, glycols, glycerol, aldehydes, ketones, benzaldehyde. aldehydes, tautomerism, physical and chemical properties of carboxylic acids, aldehydes, ketones, acid chlorides and anhydrides, amides, esters, saponification, claisen and cross claisen condensation.
6. Organic Chemistry MCQ on Nitrogen Containing Organic Compounds
The section contains Organic Chemistry MCQs on enamines, physical and chemical properties of Amines, aromatic amines preparation and properties, benzene diazonium chloride, preparation of amines and nitro compounds.
7. Organic Chemistry MCQ on Stereochemistry
The section contains Organic Chemistry multiple choice questions and answers on stereochemistry, stereoisomers, polarimeter, enantiomerism, chilarity, enantiomers, diastereomers and meso structures.
8. Organic Chemistry MCQ on Heterocyclic Compounds
The section contains Organic Chemistry questions and answers on five membered rings, structure and source of pyridine compounds, electrophilic and nucleophilc substitution in pyridine.
9. Organic Chemistry MCQ on Polymerisation & Biomolecules
The section contains Organic Chemistry MCQs on macromolecules, radical vinyl polymerisation, copolymerisation, coordination and step reaction polymerisation, amino acids, dna and rna.
Wish you the best in your endeavor to learn and master Organic Chemistry!