Problems and exercisesPhysical and Bond Properties

1. Heats of formation

Calculate the heats of formation of butane, cis- and trans-2-butene and 2-butyne from their heats of combustion (kcal/mol): −687.4, −647.7, −646.9 and −615.8, respectively. What conclusions can you draw?

Click here to recall how the calculation is done.

2. Acidity

Order from most to least acidic: ethane, ethene, ethyne, ammonia and water. Which base would you use to deprotonate propyne completely?

3. Synthesis with alkynides

Propose a synthesis of pent-2-yn-1-ol, CH₃CH₂C≡CCH₂OH, from 1-butyne.