1000 multiple choice questions in organic chemistry

Which of the following compounds does not have the molecular formula... Considering compounds of similar molecular weightand carbon chain structure, the general trend is highest to lowes

Multiple-Choice Questions in Organic Chemistry

This unit includes 1000 multiple choice questions The purpose is to assess thebreadth of student’s knowledge and understanding of the basic concepts of organicchemistry Remember that the multiple choice questions :

75 Two compounds have the same composition and also have the same atoms

attached to the same atoms, although with different orientations in space Thesecompounds are

120 Which of the following statements is correct concerning a pair of

122 A and B are stereoisomers They are nonsuperimposable and are mirror

images of one another Which of the following best describes the relationshipbetween A and B?

(b) H.

(c) HO–

(d) sulfate ion

199 Why does a H+ ion attacking a carbon-carbon double bond add to the carbonwith the least number of substituents?

(a) C-1

275 Which one of the following compounds will (a) decolorizes dilute cold

KMnO4 ; (b) decolorizes bromine water ; and (c) gives a white precipitate with

(d) Rate = k1[Alkyl Halide] + k2[Nucleophile]

(c) When a Grignard reagent reacts with a aldehyde, the addition product is a

406 Which of the following compounds does not have the molecular formula

505 An unknown compound gave a positive Tollens' test Treatment of the

unknown with I2/NaOH gave a solid which was identified as iodoform Theunknown was?

(c) aldehyde ~ ketone > carboxylic acid >> ester ~ acyl chloride ~ amide

(d) an H atom from the nitrogen is less easily lost from CH3CONH2 than from

the O considerable negative charge, thereby enhancing the H-bond acceptor

capability of the molecule Considering compounds of similar molecular weightand carbon chain structure, the general trend is (highest to lowest boiling point) :amides, carboxylic acids, alcohols, amines, aldehydes/ketones/esters, alkynes,alkenes, and alkanes

595 Partial hydrogenation of vegetable oils in the presence of Ni catalyst at

Answer. (d)

612 The N–H bond in the ammonium ion, NH4+, is formed by the overlap of whattwo orbitals?

Answer. (b) Amines are fairly polar, but they boil at temperatures lower than

those of alcohols of similar chain length and structure Amines do have higherboiling points than alkanes because they possess H-bond donors and acceptors

628 Which of the following has the highest boiling point?

(b) Glucose

Answer. (d) The numbering is done to produce the smallest total Therefore,

number from the ethyl group toward the nitro group List the substituents inalphabetic order

(d) intermediate between C–C bond length in ethane and C–C bond length in

(c) o- plus p-Xylene

(d) Toluene

Answer. (d)

802 An organic compound (A) has a molecular weight 78 and an empirical

formula CH (A) is resistant to attack by oxidizing agents but undergoes

substitution and addition reactions X-ray analysis shows that the distancebetween adjacent carbon atoms is 1.39Å (intermediate between single and double

(d) donates electrons to the ortho and para positions and attracts electrons away from meta positions favoring electrophilic attack on the ring.

Answer. (b)

828 Electron-withdrawing groups are meta directors because :

(a) the carbonium ion intermediate has a negative charge on the meta position (b) the more stable resonance hybrid occurs with meta attachment of the

Answer. (c) The aromatic amines are weaker bases than the nonaromatic cyclic

amines because the lone-pair electrons on nitrogen are delocalized over thearomatic ring This delocalization stabilizes the compound but also decreases theability of the nitrogen to act as a base Compound (3) is a stronger base thananiline because of the electron-releasing substituent on the ring

Answer. (d) Of the aromatic amines, the weakest base is the one with the

electron-withdrawing substituent: (4) is the weakest followed by aniline (3).Compound (2) is the strongest base because its electrons are not delocalized

ortho position than in the meta or para positions These intramolecular H-bonds

decrease boiling point Therefore, compound (3) has a higher boiling point thancompound (2) Compound (2), with two hydroxyl groups, has a still higher boilingpoint than phenol

936 Benzoic acid and diphenyl ketone are both solids insoluble in water A

958 Naphthalene undergoes reduction with H2 in the presence of Ni catalyst athigh temperature and pressure to give

980 How many isoprene units are in a sesquiterpene?

(a) 1