To separate a mixture of butanol and butanoic acid from its ethereal solution, two reagents can be used: NaOH (Sodium hydroxide) and NaHCO3 (Sodium bicarbonate).

1. NaOH (Sodium hydroxide):
- Sodium hydroxide is a strong base and can react with butanoic acid to form sodium butanoate, which is soluble in water.
- Sodium hydroxide does not react with butanol, so it remains unchanged in the mixture.
- By adding sodium hydroxide to the mixture, the butanoic acid will be converted into its sodium salt, while the butanol will remain in the organic layer.
- The two layers can then be separated, and the aqueous layer containing the sodium butanoate can be further processed to obtain the pure acid.

2. NaHCO3 (Sodium bicarbonate):
- Sodium bicarbonate is a weak base and can react with butanoic acid to form sodium butanoate and carbonic acid.
- Carbonic acid is unstable and decomposes into water and carbon dioxide.
- The reaction with sodium bicarbonate produces carbon dioxide gas, which causes effervescence.
- The sodium butanoate formed is soluble in water and separates from the organic layer.
- By adding sodium bicarbonate to the mixture, the butanoic acid will be converted into its sodium salt, while the butanol remains in the organic layer.
- The two layers can be separated, and the aqueous layer containing the sodium butanoate can be further processed to obtain the pure acid.

In both cases, the butanol remains in the organic layer, while the butanoic acid is converted into its sodium salt and separates into the aqueous layer. This allows for the separation of the two components of the mixture.