iGCSE Alcohols

The catalyst in the production of ethanol from ethene and steam is

• potassium dichromate (VI)

• phosphoric acid

• enzymes in yeast

• dilute sulfuric acid

The optimum temperature for the fermentation of glucose to produce ethanol is

• 50C

• 15C

• 30C

• 100C

An advantage of producing ethanol by fermentation rather than hydration of ethene is that you use lower temperature and pressure, so (a)   energy is needed.

Fermentation needs to be anaerobic or else the following would be formed instead of ethanol:

• water and carbon dioxide

• hydrogen and carbon dioxide

• water and oxygen

• carbon dioxide

Ethanol is made by reacting ethene with steam in the presence of a phosphoric acid catalyst.

Which row gives the correct conditions of temperature and pressure for this reaction?

• Temp: 35C

  Pressure: 300 atmospheres

• Temp: 65C

  Pressure: 300 atmospheres

• Temp: 300C

  Pressure: 65 atmospheres

• Temp: 300C

  Pressure: 35 atmospheres

The functional group for carboxylic acids is:

• H⁺

• C-C

• -OH

• -COOH

Ethanol can be manufactured by the fermentation of a solution of glucose.

Complete the word equation for this reaction.

glucose --> ethanol + ______ _______

(a)  

What are the two conditions required for the fermentation of glucose to produce ethanol?

• room temperature

  1 atmosphere

• 30C

  absence of air

• 300C

  65 atmospheres

• 65C

  yeast

Ethanol can be oxidised to produce a carboxylic acid.

Give the names of the two reagents used in this oxidation reaction.

• glucose

  yeast

• alkane

  chlorine

• potassium dichromate (VI)

  dilute sulfuric acid

• ethene

  steam

Ethanol can be oxidised to produce a carboxylic acid using acidified potassium dichromate (VI).

This is the colour change for the reaction:

• green to orange

• orange to green

• orange to colourless

• colourless to orange