Ethene can be converted into ethanol in industry. Fig. 10.1 shows the reaction of ethene with steam and the conditions used. Fig. 10.1 (a) Name the type of ...
Question 1 Report
Ethene can be converted into ethanol in industry. Fig. 10.1 shows the reaction of ethene with steam and the conditions used.
Fig. 10.1
(a) Name the type of reaction between ethene and steam. [1]
(b) State the three conditions used in this industrial process. [3]
(c) Name the product formed. [1]
(d) Give the molecular formula of the product. [1]
(e) State the term used to describe the adding of water across a carbon-carbon double bond. [1]
(f) Ethanol can also be made by fermentation. State two conditions needed for fermentation. [2]
(g) Give one advantage of making ethanol from ethene rather than by fermentation. [1]
(h) State the raw material from which ethene is obtained, and name the process used to obtain it. [2]
Answer Details
This question is about the industrial hydration of ethene to make ethanol, and how that route compares with fermentation.
(a) Water is added across the double bond of ethene, so the reaction is addition [1].
(b) The three conditions are [3]: a phosphoric acid catalyst [1]; a temperature of about 300 °C [1]; a pressure of about 60 atmospheres [1].
(c) The product is ethanol [1].
(d) Ethene, C2H4, gains H and OH from water, giving C2H5OH (equivalently C2H6O) [1].
(e) Adding water across a C=C double bond is called hydration [1].
(f) Fermentation needs, any two of [2]: yeast; glucose / sugar solution; a warm temperature about 25 to 35 °C; the absence of air (anaerobic conditions).
(g) One advantage of the ethene route is that it is faster / a continuous process / gives a higher yield / needs less labour (any one) [1].
(h) Ethene is obtained from crude oil / petroleum [1], by cracking [1].
Exam reminder: hydration (adding water) makes ethanol from ethene, while fermentation makes ethanol from sugar; do not confuse the two routes or their conditions.
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