Substitution Reactions of Alkanes

This video tutorial by Ms. Cam explores the reactions of alkanes, focusing on their low reactivity due to non-polar carbon-hydrogen bonds and strong carbon-carbon bonds. It covers the combustion reactions of alkanes, distinguishing between complete and incomplete combustion, and the products formed in each case. The video also delves into substitution reactions, explaining the initiation, propagation, and termination steps, highlighting the role of free radicals and UV light in these processes.

Why do alkanes exhibit low reactivity?

• Due to weak carbon bonds

• Due to high electronegativity

• Because they have polar bonds

• Because of non-polar and strong bonds

What is produced during the complete combustion of alkanes?

• Carbon and hydrogen

• Carbon dioxide and water

• Methane and oxygen

• Carbon monoxide and water

What happens in incomplete combustion of alkanes?

• Excess oxygen is present

• Carbon dioxide is the only product

• Carbon monoxide or carbon is produced

• Only water is produced

What initiates the substitution reaction in alkanes?

• Excess oxygen

• High temperature

• UV light

• Presence of water

What is formed when a chlorine molecule breaks in the initiation step?

• Chlorine atoms

• Chlorine gas

• Chlorine free radicals

• Chlorine ions

What is the main characteristic of the propagation step in substitution reactions?

• It requires high pressure

• It is a chain reaction

• It involves the formation of ions

• It is a slow reaction

What is produced when a methyl radical reacts with molecular chlorine?

• Chloroethane

• Methane

• Hydrogen chloride

• Ethane

What occurs during the termination step of substitution reactions?

• Free radicals are formed

• Free radicals pair up to form molecules

• New radicals are generated

• The reaction speeds up

Which of the following is a product of the overall substitution reaction of methane with chlorine?

• Ethane

• Chloroethane

• Methane

• Carbon dioxide

What is the role of UV light in the substitution reaction of alkanes?

• It slows down the reaction

• It breaks the chlorine molecule into radicals

• It combines radicals

• It forms water