(a) Draw two isomeric structures of Butene (C₄H₈)

(b) Name the following compounds :

(c) Write the chemical equations for the following reactions. Mention one essential condition each for these reactions to take place.

1. Ethanol undergoes complete oxidation
2. Propene undergoes hydrogenation
3. Ethanoic acid reacts with ethanol

(a) Butene (C₄H₈) has two possible structural isomers due to the position of the double bond:

1. 1-butene

2. 2-butene

(b)

1. 1-chloropropane

2. butan-2-one

(c)

1. Complete oxidation of ethanol :

$\text C$2 \text H5 \text {OH} + 3\text O2 \longrightarrow 2\text {CO}2 + 3\text H_2 \text O

Essential condition : Sufficient (excess) oxygen and ignition/heat so combustion proceeds to CO₂ and H₂O.

2. Hydrogenation of propene :

$\text C$3 \text H6 + \text H2 \xrightarrow {\text {Ni, Pt or Pd}} \text C3 \text H_8

Essential condition : Presence of hydrogen and a hydrogenation catalyst (e.g. nickel, platinum or palladium) — often with mild heating/pressure.

3. Ethanoic acid reacts with ethanol (esterification) :

$\text {CH}$3\text {COOH} + \text C2 \text H5 \text {OH} \xrightarrow {\text {conc.} \text H2 \text {SO}4} \text {CH}3\text {COO} \text C2 \text H5 + \text H_2 \text O

Essential condition : Acid catalyst (concentrated H₂SO₄) and gentle heating (reflux) to form ethyl ethanoate; removal of water drives the equilibrium to the right.