Propene formation and properties Steps:

• Recall propene's formula: C3H6, an alkene with a C=C double bond.
• Evaluate each option against hydrocarbon definitions and reactions.
• Identify cracking as a process breaking larger alkanes into smaller alkenes/alkanes.
• Confirm hydrogenation product: propene + H2 yields propane (C3H8), not ethane.

Why B is correct:

• Cracking butane (C4H10) thermally or catalytically breaks C-C bonds, producing propene (C3H6) + CH4, as per industrial alkene synthesis.

Why the others are wrong:

• A: Propene is C3H6; butane is C4H10—formulas differ.
• C: Propene has a double bond, making it unsaturated, not saturated.
• D: Hydrogenation adds H2 across the double bond to form propane (C3H8), not ethane (C2H6).

Final answer: B