The standard reduction potential of a half-cell measures:
A. Resistance of electrolyte
B. Tendency to gain electrons
C. Tendency to lose electrons
D. Current produced
Answer: Option B
Solution (By JKExamLibrary)
Standard reduction potential (E°) measures the tendency of a species to gain electrons and be reduced. The more positive the E°, the greater the tendency to undergo reduction. Metals with negative E° are good reducing agents (e.g., Zn, -0.76 V). E°cell = E°cathode - E°anode. It is measured under standard conditions (1 M, 1 atm, 25°C) relative to standard hydrogen electrode (SHE) which is assigned 0 V.
Explanation:
Fajan's rules state that covalent character in an ionic bond increases with greater polarizing power of the cation and greater polarizability of the anion. A small cation has high charge density (high polarizing power), and a large anion has loosely held outer electrons (high polarizability), favoring covalency.
Explanation:
Magnesium loses two electrons to achieve noble gas configuration (Mg → Mg²⁺), so its electrovalency is +2. In MgCl₂, Mg²⁺ and two Cl⁻. Electrovalency is the charge on the ion. Covalency is number of covalent bonds. For Group 2 metals, electrovalency is always +2 (loss of 2 electrons).
Explanation:
Chlorofluorocarbons (CFCs) release chlorine atoms in stratosphere which catalytically destroy ozone. CO₂ causes global warming, SO₂ acid rain, N₂ is inert. Ozone hole over Antarctica is due to CFCs.
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