Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
231–240 of 335 · Normal
Question 231
6 marks · Normal
Answer and see the solution →A student carries out two experiments: (A) heating ethanol with potassium dichromate(VI) in dilute sulfuric acid, and (B) producing ethanol by fermentation.
(a)[1 mark]In experiment A, state the colour change that occurs when ethanol is successfully oxidised.
(b)[1 mark]Name the final organic product formed in experiment A.
(c)[1 mark]In experiment B, yeast is added to a sugar solution. State one condition required to maximise ethanol production by fermentation.
(d)[3 marks]Complete the table below for each experiment.
Experiment Reactants Product A B Question 232
6 marks · Normal
Answer and see the solution →The two main industrial sources of ethanoic acid are laboratory oxidation of ethanol and microbial fermentation to produce ethanol. The steps below investigate both processes.
(a)[3 marks]A laboratory technician oxidises 4.6 g of ethanol (CH2OH, molar mass = 46 g/mol) using excess potassium dichromate(VI) in dilute sulfuric acid as the oxidising agent. Calculate the maximum mass of ethanoic acid (COOH, molar mass = 60 g/mol) that could be obtained.
(b)[1 mark]Explain the role of dilute sulfuric acid in the oxidation of ethanol with potassium dichromate(VI).
(c)[2 marks]Another technician produces ethanol by fermentation. State the conditions required for the fermentation of glucose to produce ethanol.
Question 233
6 marks · Normal
Answer and see the solution →Ethanol can be prepared by fermentation or it can be oxidised in the laboratory.
(a)Describe how ethanol can be oxidised using potassium dichromate(VI) in dilute sulfuric acid. Include what you would observe during the process.
(i)[1 mark]Describe the method used, including reagents and condition.
(ii)[1 mark]State the observable colour change that shows oxidation has occurred.
(iii)[1 mark]Name the organic product formed.
(b)Explain how ethanol can be produced by fermentation. Include two conditions that are essential for this process.
(i)[1 mark]State the process used and the starting material.
(ii)[2 marks]Give two conditions that ensure ethanol is produced, not other products.
Question 234
2 marks · Normal
Answer and see the solution →State the number of carbon atoms AND draw the structural formula of propanoic acid.
Question 235
4 marks · Normal
Answer and see the solution →This question is about naming carboxylic acids.
(a)[1 mark]Give the name of the carboxylic acid with molecular formula C4H8O2.
(b)[2 marks]Write the name and structural formula of the carboxylic acid with molecular formula CH2O2.
(c)[1 mark]State how you determine the name of a straight-chain carboxylic acid from its molecular formula.
Question 236
3 marks · Normal
Answer and see the solution →Explain how you can identify whether a molecule is a carboxylic acid, using both its structural formula and its name.
Question 237
4 marks · Normal
Answer and see the solution →The table below shows the molecular formulae of some carboxylic acids. Complete the table by filling in the missing names.
Carboxylic acids to name Molecular formula Name C2H4O2 C4H8O2 CH2O2 C3H6O2 Write your answers in the table.
Question 238
1 mark · Normal
Answer and check →Which of the following gives the main component of vinegar?
- A.methanoic acid
- B.propanoic acid
- C.ethanoic acid
- D.butanoic acid
Question 239
2 marks · Normal
Answer and see the solution →Give the molecular formula and the displayed formula for butanoic acid.
Question 240
4 marks · Normal
Answer and see the solution →The table shows several unbranched carboxylic acids:
Name Molecular formula methanoic acid CH2O2 propanoic acid C3H6O2 (a)[2 marks]Write the name and structural formula of the carboxylic acid with the molecular formula C2H4O2.
(b)[2 marks]State the number of carbon atoms in butanoic acid and write its name following IUPAC conventions.