Question 19N.3.sl.TZ0.2b
| Date | November 2019 | Marks available | [Maximum mark: 1] | Reference code | 19N.3.sl.TZ0.2b |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | Deduce, Justify | Question number | b | Adapted from | N/A |
Ethanol was electrolysed at different voltages. The products at the anode, ethanoic acid, ethanal and carbon dioxide, were collected and analysed.
The percentages of products obtained using three different catalysts mounted on a carbon anode, platinum (Pt/C), platinum and ruthenium alloy (PtRu/C) and platinum and tin alloy (PtSn/C) are shown.
Chemical yields of ethanoic acid, ethanal and carbon dioxide as a function of voltage for
oxidation of 0.100 mol dm−3 ethanol at Pt/C, PtRu/C and PtSn/C anodes at 80°C.
[Source: Product Distributions and Efficiencies for Ethanol Oxidation in a Proton Exchange Membrane Electrolysis Cell, Rakan M. Altarawneh and Peter G. Pickup, Journal of the Electrochemical Society, 2017, volume 164, issue 7, http://jes.ecsdl.org/. Distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/)]
Deduce, giving your reason, which catalyst is most effective at fully oxidizing ethanol.
[1]
Pt/platinum/PtC AND highest yield of CO2 «at all voltages» ✔
NOTE: ECF from 2aiii.
