ALKANE

What is the general formula for alkanes?

• CnH2n

• CnH2n-2

• CnH2n+2

• CnHn+2

Answer explanation

The general formula for alkanes is CnH2n+2. This formula represents that for every carbon atom, there are two hydrogen atoms plus two additional hydrogen atoms.

Name the first four alkanes in the series.

• Sodium, Magnesium, Aluminum, Silicon

• Carbon, Nitrogen, Oxygen, Fluorine

• Hydrogen, Helium, Lithium, Beryllium

• Methane, Ethane, Propane, Butane

Answer explanation

The first four alkanes in the series are Methane, Ethane, Propane, and Butane. These are the correct choices.

How do you name alkanes using IUPAC nomenclature?

• By counting the number of hydrogen atoms

• By identifying the shortest continuous carbon chain

• By adding a prefix based on the number of carbon atoms

• By identifying the longest continuous carbon chain and adding the appropriate suffix based on the number of carbon atoms.

Answer explanation

Alkanes are named using IUPAC nomenclature by identifying the longest continuous carbon chain and adding the appropriate suffix based on the number of carbon atoms. This ensures accurate naming of the compound.

What is structural isomerism in alkanes?

• Compounds with different molecular formulas but the same structural arrangement of atoms.

• Compounds with the same molecular formula and the same structural arrangement of atoms.

• Compounds with different molecular formulas and different structural arrangements of atoms.

• Different compounds with the same molecular formula but different structural arrangements of atoms.

Answer explanation

Structural isomerism in alkanes refers to different compounds with the same molecular formula but different structural arrangements of atoms.

Provide an example of two structural isomers of a specific alkane.

• 2-methylpropane and n-butane

• propane and butane

• ethanol and methanol

• ethane and pentane

Answer explanation

Two structural isomers of a specific alkane are 2-methylpropane and n-butane. These compounds have different arrangements of carbon atoms, resulting in distinct chemical properties.

What are the physical properties of alkanes?

• Nonpolar, high solubility in water, high melting and boiling points

• Nonpolar, low solubility in water, low melting and boiling points

• High solubility in water, high melting and boiling points, polar

• High solubility in water, low melting and boiling points, polar

Answer explanation

Alkanes are nonpolar and have low solubility in water, as well as low melting and boiling points. This matches the correct choice.

How do the boiling points of alkanes change with increasing carbon chain length?

• Boiling points fluctuate

• Boiling points increase

• Boiling points remain constant

• Boiling points decrease

Answer explanation

The boiling points of alkanes increase with increasing carbon chain length.

What are the chemical properties of alkanes?

• Low reactivity, susceptibility to oxidation, and explosive

• Medium reactivity, resistance to oxidation, and non-flammable

• High reactivity, susceptibility to oxidation, and non-combustible

• Low reactivity, resistance to oxidation, and combustion

Answer explanation

Alkanes have low reactivity, resistance to oxidation, and combustion. This makes them less likely to undergo chemical reactions and more stable when exposed to oxygen and heat.

Why are alkanes considered to be relatively inert?

• Easily breakable bonds

• Strong carbon-carbon and carbon-hydrogen bonds

• High reactivity with other elements

• Weak carbon-carbon and carbon-hydrogen bonds

Answer explanation

Alkanes are considered relatively inert due to their strong carbon-carbon and carbon-hydrogen bonds, which make them resistant to reactions with other elements.

What is the combustion of alkanes?

• Reaction of alkanes with oxygen to produce carbon dioxide and water

• Reaction of alkanes with sulfur to produce sulfur dioxide and water

• Reaction of alkanes with nitrogen to produce carbon monoxide and water

• Reaction of alkanes with hydrogen to produce methane and oxygen

Answer explanation

The combustion of alkanes refers to the reaction of alkanes with oxygen to produce carbon dioxide and water.