Metallurgy Long Ans Concise Class-10 ICSE Chemistry Selina Solutions Chapter-7. We Provide Step by Step Answer of Long Ans Questions of Miscellaneous Exercise-7 for ICSE Class-10. The given Solutions is according to the Latest editions. Visit official Website CISCE for detail information about ICSE Board Class-10.
Metallurgy Long Ans Concise Class-10 ICSE Chemistry Selina Solutions Chapter-7
| Board | ICSE |
| Book / Publication | Concise / Selina |
| Subject | Chemistry |
| Class | 10th |
| Writer | Dr SP Singh |
| Chapter-7 | Metallurgy |
| Topics | Long Ans (Miscellaneous Exercise) |
| Edition | 2025-2026 |
Long Ans Questions on Metallurgy
Page-143
Que-1: The following is an extract from ‘Metals in the Service of man, Alexander and street/Pelican 1976′.’
“Alumina (aluminium oxide) has a very high melting point of over 2000oC so that it cannot readily be liquefied. However, conversion of alumina to aluminium and oxygen, by electrolysis, can occur when it is dissolved in some other substance”.
(a) Which solution is used to react with bauxite as first step in obtaining pure aluminium oxide?
(b) The aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide. Write the equation for the reaction.
(c) Name the element which serves both as anode and cathode in the extraction of aluminium.
(d) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.
(e) Give the equation for the reaction which occurs at the anode when aluminium is purified by electrolysis.
Ans:
(a) Sodium hydroxide
(b) 2Al(OH)3 (Heat) ⟶ (1000°C) Al2O3 +3H2O
(c) Graphite
(d) Reaction at cathode: Al3+ + 3e– ⟶ Al
(e) Reaction at anode: Al – 3e– ⟶ Al3+
Que-2: The following is a sketch of an electrolytic cell used in the extraction of aluminium:
(i) What is the substance of which the electrodes A and B are made?
(ii) At which electrode (A or B) is the aluminium formed?
(iii) What are the two aluminium compounds in the electrolyte C?
(iv) Why is it necessary for electrode B to be continuously replaced?
Ans:
(a) A is made of carbon and B is thick graphite rod.
A ⟶ Cathode
B ⟶ Anode
(b) Aluminium is formed at electrode A.
(c) The two aluminium compound in the electrolyte C is Na3AlF6, Al2O3.
(d) It is necessary to continuously replace electrode B from time to time as it gets oxidized by the oxygen evolved.
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