Chemistry - Study Mode
[#606] Aluminium can be purified by
Correct Answer
(C) Electrolysis
Explanation
Solution: Electrolysis is a method of using a direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially highly important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. Aluminum is extracted from its oxide ore “Bauxite”. Electrolytic smelting of alumina was originally cost-prohibitive in part because of the high melting point of alumina, or aluminium oxide. Many minerals, however, will dissolve into a second already molten mineral, even if the temperature of the melt is significantly lower than the melting point of the first mineral. Molten cryolite was discovered to dissolve alumina at temperatures significantly lower than the melting point of pure alumina without interfering in the smelting process.
[#607] The aqueous solution of potassium chloride is
Correct Answer
(B) A strong electrolyte
Explanation
Solution: Potassium chloride (KCl) is a strong electrolyte because it completely diassociates into positively charged potassium ions.
[#608] Sodium is produced by the electrolysis of
Correct Answer
(B) Molten sodium chloride
Explanation
Solution: Sodium is produced by the electrolysis of molten sodium chloride.
[#609] Bleaching powder is prepared by passing :
Correct Answer
(A) Chlorine over slaked lime
Explanation
Solution: Bleaching powder is prepared by passing chlorine gas over dry slaked lime Ca(OH) 2 by Hesenclaver method or by Bachmann method.
[#610] Most commonly used bleaching agent is
Correct Answer
(D) Chlorine
Explanation
Solution: Chlorine is the most commonly used bleaching agent.
Bleaching agents are compounds which are used to remove color from substances such as textiles. A bleaching agent is a material that lightens or whitens a substrate through the chemical reaction. The bleaching reactions usually involve oxidative or reductive processes that degrade color systems.