A student set up the apparatus shown in Fig. 1.1 to electrolyse a solution using two carbon electrodes. Four parts of the apparatus are labelled W, X, Y and...
Question 1 Report
A student set up the apparatus shown in Fig. 1.1 to electrolyse a solution using two carbon electrodes. Four parts of the apparatus are labelled W, X, Y and Z. Electrode X is joined to the negative terminal.
(a) Name the piece of apparatus labelled W. [1]
(b) Name the two parts labelled X and Y. [1]
(c) X is joined to the negative terminal. State the name given to this electrode. [1]
(d) Name the liquid labelled Z through which the current passes. [1]
(e) State why carbon is chosen for the electrodes X and Y. [1]
Answer Details
This question tests the names of the parts of a simple electrolysis cell. In electrolysis a direct current is passed through a liquid that conducts, and the two rods dipping into it carry the current in and out.
(a) W is the d.c. power supply / battery [1]. Electrolysis needs direct current so that each electrode keeps a fixed charge.
(b) X and Y are the two (carbon) electrodes [1].
(c) X is joined to the negative terminal, so it is the cathode [1]. The cathode is always the negative electrode, where positive ions are attracted and gain electrons.
(d) Z is the electrolyte [1], the liquid (a molten ionic compound or an ionic solution) through which the current passes because it contains free-moving ions.
(e) Carbon is chosen because it is inert / unreactive and conducts electricity, so it carries the current but does not react or change during the electrolysis [1].
Download The App On Google Playstore
Everything you need to excel in your exams
