Show how to prepare: (a) acetylene from ethylene. (b) 1-butyne from acetylene.

(a) To prepare acetylene from ethylene, you can follow the following steps:

1. Start with ethylene gas (C2H4).
2. Pass the ethylene gas through a high-temperature environment (around 800-900 degrees Celsius) in the presence of a catalyst such as nickel or platinum. This process is known as pyrolysis or cracking.
3. The high temperature causes the ethylene molecules to break apart, forming acetylene gas (C2H2) as one of the products.
4. Acetylene gas can then be collected and stored for further use.

(b) To prepare 1-butyne from acetylene, you can follow the following steps:

1. Start with acetylene gas (C2H2).
2. React the acetylene gas with a strong base such as sodium amide (NaNH2) in liquid ammonia (NH3) at low temperatures.
3. The base will deprotonate the acetylene molecule, forming the corresponding alkyne, which in this case is 1-butyne (C4H6).
4. The 1-butyne product can then be isolated and purified for further use.