In the refining of copper by electrolytic refining, the anode is:
A. Graphite
B. Pure copper
C. Platinum
D. Impure copper
Answer: Option D
Solution (By JKSSB Mock Tests)
In electrolytic refining of copper, impure copper is used as the anode, a thin sheet of pure copper as the cathode, and CuSO₄ acidified with H₂SO₄ as electrolyte. On passing current, copper dissolves from the anode and pure copper deposits on the cathode. Impurities like gold, silver fall as anode mud. This yields 99.99% pure copper. Similar process for other metals.
Explanation:
Using Boyle's law: P₁V₁ = P₂V₂ => 2 atm × 5 L = 1 atm × V₂ => V₂ = 10 L. As pressure decreases, volume increases. The same mass of gas expands. This is a direct application of inverse proportionality. If temperature and amount of gas are constant, doubling pressure halves volume, etc.
Explanation:
Mercury (Hg) is the only metal that is liquid at room temperature. Gallium and cesium melt slightly above room temperature. Sodium is solid but soft. Zinc and aluminium are solids. Mercury is used in thermometers and barometers.
Explanation:
At anode (oxidation): 2Cl⁻ → Cl₂ + 2e⁻ (chlorine gas). At cathode (reduction): Na⁺ + e⁻ → Na (liquid sodium). In aqueous NaCl, due to water, cathode produces H₂ and anode Cl₂ (or O₂ depending on concentration).
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