Alcohols react with sodium
Hydrogen is given off.
Sodium meets ethanol
A teacher drops a small piece of sodium into ethanol in the lab. You watch from a distance.
What do you think is given off?
What this lesson covers
The idea
Alcohols react with sodium with the evolution of hydrogen; with ethanol the other product is sodium ethoxide.
Sodium meets ethanol
A teacher drops a small piece of sodium into ethanol in the lab. You watch from a distance.
What do you think is given off?
- Hydrogen
- Oxygen
- Carbon dioxide
Sodium in ethanol
Press Next step. A teacher does this in the lab.
Hydrogen from alcohols
Sodium takes the place of the hydrogen of the -OH group. That hydrogen leaves as a gas.
Alcohols react with sodium with the evolution of hydrogen. With ethanol, the other product is sodium ethoxide.
Notes
Alcohols react with sodium with the evolution of hydrogen. With ethanol, the other product is sodium ethoxide.
Check yourself
Which gas is given off when an alcohol reacts with sodium?
What is the other product when ethanol reacts with sodium?
Which of these reacts with alcohols to evolve hydrogen?
In 2Na + 2CH₃CH₂OH giving 2CH₃CH₂O⁻Na⁺ + H₂, how many molecules of hydrogen, H₂, are formed?
Answer: 1
The equation shows one H₂.
- Oxygen. The book says hydrogen is evolved.
- Hydrogen — correct. Yes!
- Carbon dioxide. Carbon dioxide is given off when ethanoic acid reacts with carbonates and hydrogencarbonates. Alcohols and sodium give hydrogen.
- Sodium ethanoate. Sodium ethanoate (sodium acetate) forms when ethanoic acid reacts with a base or a carbonate.
- Ethene. Ethene forms when ethanol is heated with excess concentrated sulphuric acid.
- Sodium ethoxide — correct. Yes!
- Sodium — correct. Yes!
- Concentrated sulphuric acid. On heating, it removes water from ethanol to give ethene.
- Alkaline potassium permanganate. It adds oxygen, oxidising alcohols to carboxylic acids.