When electric current is passed through water, its decomposition takes place and gas bubbles are formed at electrodes. (i) Name the electrode and electrolyte used in above activity. (ii) Which gas bubbles are formed at a) Cathode b) Anode (iii) Why do we add few drops of acid or small amount of salt in the above set up? (b) ’Both taps, car bumpers’ are coated with chromium. Why? (c) Çertain metals are extracted from their ores by the process of electrolysis’. Name the process.
Answers
Answer:
1) The electrolyte is water and electrode is anode & cathode
2) The gas over cathode is hydrogen & gas over anode is oxygen.
Explanation:
Don't know the rest... Sorry.
(i) Platinum electrode is used in the electrolysis of water, as platinum is a good conductor of electricity and does not react with the water.
(ii) a) At Cathode Hydrogen gas bubbles are formed.
H⁺ ions are positive ions that are attracted towards the cathode (negative electrode). At the cathode, H⁺ are reduced to form hydrogen gas
b) At anode oxygen gas is evolved. O²⁻ ions are negative ions that are attracted towards the anode (positive electrode). At the anode, these ions are oxidized to form oxygen gas.
(iii) We add a little amount of salt to increase the conductance of the water as water is a poor conductor and saltwater is a good conductor. This increases the speed of electrolysis.
(b) Taps and car bumpers are made of chromium to make them resistant to rust and more durable.
(c)The process is known as electrolytic reduction. It is commonly used for extracting metals from oxide ores.