Question 1

Which of the following statements best describes a functional group in organic chemistry?

Accepted Answer

A group of atoms responsible for the characteristic chemical properties and reactions of a molecule.

Question 2

What is the general formula for alkanes?

Accepted Answer

$$\mathrm{C_nH_{2n+2}}$$

Question 3

Which of the following best describes the bonding in alkanes?

Accepted Answer

Only carbon-carbon single bonds formed from $$\sigma-$$overlap of $$sp^3$$ hybrid orbitals.

Question 4

Which of the following is the correct IUPAC name for the compound with the structure: $$\mathrm{CH_3$-CH_2$-CH(CH_3$)-CH_2$-CH_3$}$$?

Accepted Answer

3-Methylpentane

Question 5

Which type of carbon atom is bonded to three other carbon atoms?

Accepted Answer

Tertiary ($$3^\circ) $$carbon

Question 6

Which conformation of ethane is the most stable?

Accepted Answer

Staggered conformation

Question 7

What is the main reason alkanes are insoluble in water?

Accepted Answer

They lack polar groups capable of forming hydrogen bonds.

Question 8

How does branching in a hydrocarbon chain affect its lipophilicity?

Accepted Answer

Branching decreases lipophilicity by making the chain more compact.

Question 9

Which of the following is a major chemical reaction of alkanes?

Accepted Answer

Combustion in oxygen to produce water and carbon dioxide.

Question 10

What is the product of the reaction: $$\mathrm{CH_4$ + Cl_2$ \xrightarrow{hv} CH_3Cl + HCl}$$?

Accepted Answer

Chloromethane ($$\mathrm{CH_3Cl})$$

Question 11

Which of the following best describes the mechanism of alkane halogenation?

Accepted Answer

Free radical mechanism initiated by UV light or high temperature.

Question 12

What is the effect of increasing alkyl chain length on the pharmacological activity of a drug molecule?

Accepted Answer

It increases the lipophilic character, affecting absorption, distribution, and excretion.

Question 13

Which of the following is true about the chair conformation of cyclohexane?

Accepted Answer

It is strain-free and has six axial and six equatorial hydrogens.

Question 14

Which of the following statements about the combustion of alkanes is correct?

Accepted Answer

Combustion is an exothermic reaction producing $$\mathrm{CO_2$}$$ and $$\mathrm{H_2O}.$$

Question 15

Which of the following is the correct IUPAC name for the compound: $$\mathrm{CH_3$-CH(CH_3$)-CH_2$-CH_2$-CH_3$}$$?

Accepted Answer

2-Methylpentane

Question 16

Which of the following is a consequence of the chair conformation of cyclohexane?

Accepted Answer

There are two kinds of positions for hydrogens: axial and equatorial.

Question 17

Which of the following is NOT a property of alkanes?

Accepted Answer

They are reactive towards acids and bases.

Question 18

What is the order of reactivity for C-H bonds in branched chain hydrocarbons?

Accepted Answer

Tertiary C-H \u003c Secondary C-H \u003c Primary C-H

Question 19

Which of the following best explains why general anaesthetic alkanes partition rapidly into the lipid portion of the brain?

Accepted Answer

Alkanes are highly lipophilic and dissolve readily in lipids.

Alkanes: Structure, Properties, and Reactivity

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