CIE iGCSE Co-Ordinated Science C11.6 Alcohols Exam Style Questions Paper 1
▶️ Answer/Explanation
Fermentation is the process in which yeast breaks down sugar into ethanol and carbon dioxide: \( C_6H_{12}O_6 \rightarrow 2C_2H_5OH + 2CO_2 \).
This biological process is the standard method used to produce ethanol.
✅ Answer: (D)
This biological process is the standard method used to produce ethanol.
✅ Answer: (D)
▶️ Answer/Explanation
Ethanol is traditionally produced biologically, using yeast to convert sugar into ethanol and carbon dioxide.
This biological process is called fermentation, and is carried out in the absence of oxygen.
Reacting ethene with steam (not listed here) is the industrial alternative, while the other listed reactions do not produce ethanol.
✅ Answer: (A)
This biological process is called fermentation, and is carried out in the absence of oxygen.
Reacting ethene with steam (not listed here) is the industrial alternative, while the other listed reactions do not produce ethanol.
✅ Answer: (A)
▶️ Answer/Explanation
Complete combustion occurs when there is a plentiful supply of oxygen.
Ethanol, \( C_2H_5OH \), contains carbon, hydrogen and oxygen, so complete combustion converts all the carbon to carbon dioxide and all the hydrogen to water.
Carbon monoxide would only form from incomplete combustion, and hydrogen gas is not a combustion product.
✅ Answer: (B)
Ethanol, \( C_2H_5OH \), contains carbon, hydrogen and oxygen, so complete combustion converts all the carbon to carbon dioxide and all the hydrogen to water.
Carbon monoxide would only form from incomplete combustion, and hydrogen gas is not a combustion product.
✅ Answer: (B)
Question
Four molecules are shown.
Which structure represents ethanol?
A. H–C–C–OH
B. H–C–O–C–H
C. H–C–C–H
D. H–C–O–H
▶️Answer/Explanation
Answer: A. H–C–C–OH
Explanation: Ethanol has the molecular formula C₂H₅OH, which corresponds to the structure H–C–C–OH.
Question
Ethanol is manufactured by reacting ethene with steam in the presence of a catalyst. Which type of reaction occurs?
A addition
B oxidation
C polymerisation
D reduction
▶️Answer/Explanation
Answer: A addition
Explanation: The reaction between ethene and steam to produce ethanol is an addition reaction, where water (H₂O) adds across the double bond of ethene (C₂H₄).