Chemistry 9th Chap 14 : Topic 1 - Maryam Publications

Chemistry Chapter 14 : Topic 1

Alkanes and Saturation

1 / 18

Alkanes are described as saturated hydrocarbons because they contain a carbon skeleton in which each carbon atom forms single covalent bonds only, allowing the maximum number of hydrogen atoms to attach. Which statement best explains this property?

A) Alkanes contain only single covalent bonds and cannot add more hydrogen atoms without breaking existing bonds.

B) Alkanes have carbon atoms bonded with hydrogen only through ionic bonds.

C) Alkanes always contain oxygen atoms in their structure.

D) Alkanes contain at least one double bond between carbon atoms.

2 / 18

A student observes a hydrocarbon with molecular formula C₄H₁₀ and concludes it is an alkane. Which reasoning correctly supports this conclusion?

A) It has equal numbers of carbon and hydrogen atoms.

B) It follows the general formula CₙH₂ₙ₊₂ indicating saturation.

C) It contains a carbon-carbon triple bond.

D) It forms ionic compounds with metals.

3 / 18

In methane (CH₄), carbon forms four single covalent bonds. What does this indicate about carbon’s bonding nature in alkanes?

A) Carbon forms only ionic bonds in alkanes.

B) Carbon loses four electrons completely.

C) Carbon shares electrons to complete its valency through single covalent bonds.

D) Carbon cannot bond with hydrogen.

4 / 18

Which of the following best distinguishes alkanes from alkenes?

A) Alkanes contain only single covalent bonds and are saturated.

B) Alkanes react easily with bromine water without conditions.

C) Alkanes are unsaturated and contain double bonds.

D) Alkanes contain triple bonds between carbon atoms.

5 / 18

A hydrocarbon undergoes substitution reaction instead of addition reaction. What does this indicate about its structure?

A) It contains ionic bonding.

B) It is an alcohol.

C) It contains a double bond.

D) It is saturated with only single covalent bonds.

6 / 18

Which statement correctly explains why alkanes are called “saturated”?

A) They dissolve in water completely.

B) They contain maximum possible hydrogen atoms bonded to carbon.

C) They are highly reactive due to double bonds.

D) They contain oxygen atoms in all molecules.

7 / 18

Consider a hydrocarbon with only single bonds between carbon atoms and hydrogen atoms attached to carbon. What type of hydrocarbon is it?

A) Alkane

B) Alcohol

C) Alkyne

D) Alkene

8 / 18

Why are alkanes generally less reactive compared to alkenes?

A) They dissolve in acids.

B) They have only single covalent bonds with no weak double bonds.

C) They contain oxygen atoms.

D) They have strong ionic bonds.

9 / 18

The general formula of alkanes is CₙH₂ₙ₊₂. What does this formula indicate?

A) Formation of ionic compounds

B) Saturation of carbon atoms with hydrogen

C) Presence of double bonds

D) Presence of oxygen in structure

10 / 18

Which of the following hydrocarbons is definitely an alkane?

A) C₂H₂

B) C₃H₆

C) C₅H₁₂

D) C₂H₄

11 / 18

A teacher explains that alkanes cannot decolorize bromine water easily. What is the correct scientific reason?

A) They contain ionic bonds.

B) They contain oxygen atoms.

C) They are saturated hydrocarbons with no double bonds.

D) They are soluble in bromine water.

12 / 18

Which statement best describes bonding in alkanes?

A) Carbon atoms are joined by single covalent bonds only.

B) Hydrogen atoms are not bonded to carbon.

C) Carbon atoms are joined by double covalent bonds.

D) Carbon atoms are joined by ionic bonds.

13 / 18

Why does methane (CH₄) not show addition reactions?

A) It is saturated with single covalent bonds only.

B) It has ionic bonding.

C) It contains oxygen atoms.

D) It contains double bonds.

14 / 18

Which structural feature confirms a hydrocarbon is an alkane?

A) Presence of C=C bond

B) Only C-C single bonds

C) Presence of C≡C bond

D) Presence of hydroxyl group

15 / 18

A hydrocarbon is found to have maximum hydrogen atoms bonded to carbon atoms. What conclusion is correct?

A) It is unsaturated.

B) It is an acid.

C) It is an alcohol .

D) It is an alkane.

16 / 18

Which property is NOT associated with alkanes?

A) Saturated structure

B) High reactivity due to double bonds

C) Single covalent bonds

D) General formula CₙH₂ₙ₊₂

17 / 18

Why are alkanes classified as hydrocarbons?

A) They contain carbon and hydrogen only.

B) They contain oxygen and hydrogen.

C) They contain metals and carbon.

D) They contain ions only.

18 / 18

What happens if an alkane is forced to form more bonds than possible?

A) It changes into an alkene.

B) It becomes more stable.

C) Existing bonds must break, showing saturation limit.

D) It forms ionic compounds.

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