How would you convert:

(a) ethyl bromide into ethene

(b) ethene into 1,2-dibromoethane

(c) ethene into ethane

(a) ethyl bromide into ethene : Dehydrohalogenation

$\underset{\text{ Bromo ethane [ethyl bromide]}}{\text{C}$2\text{H}5\text{Br}} + \underset{\text{alcoholic, hot and conc.}}{\text{KOH}} \longrightarrow \underset{\text{ethene [ethylene]}}{\text{C}2\text{H}4} + \text{KBr} + \text{H}_2\text{O}

(b) ethene into 1,2-dibromoethane : Halogenation

$\underset{\text{ ethene}}{\text{C}$2\text{H}4} + \text{Br}2 \xrightarrow[\text{[inert solvent]}]{\text{CCl}4} \underset{\text{1,2, dibromooethane [ethylene bromide]}}{\text{C}2\text{H}4\text{Br}_2}

(c) ethene into ethane : Hydrogenation

$\underset{\text{ ethene [ethylene]}}{\text{H}$2\text{C}=\text{C}\text{H}2} + \text{H}2 \xrightarrow[200\degree\text{C}]{\text{Nickle}} \underset{\text{ethane}}{\text{C}2\text{H}_6}