JEE Chemistry - MCQ Practice Questions

Electrical conductivity is measured in Siemens per meter (S·m⁻¹). Ω·m is the unit of resistivity, which is the inverse of conductivity.

In a galvanic cell, the anode is the negative electrode where oxidation occurs. The cathode is positive where reduction occurs.

Faraday's first law states that the mass of substance deposited/dissolved during electrolysis is directly proportional to the quantity of electricity (charge) passed through the electrolyte.

The Nernst equation: E = E° - (RT/nF)ln(Q) calculates the cell potential when concentrations are not at standard state (1 M).

A dry cell or Leclanche cell is a primary cell that cannot be recharged. Lead-acid and Ni-Cd are secondary cells; Li-ion is rechargeable.

In electroplating, the object to be plated is made the cathode (negative terminal) where reduction occurs, causing metal deposition.

In a galvanic cell, oxidation occurs at the anode. The anode is the negative electrode where electrons are released and the species loses electrons.

Faraday constant (F) = 96485 Coulombs per mole of electrons. This represents the charge carried by one mole of electrons.

By international convention, the standard reduction potential of H⁺/H₂ couple is taken as 0.00 V at 25°C. This serves as the reference electrode for all other electrode potentials.

For a spontaneous cell reaction, E°cell > 0 (positive). When E°cell is negative, the reaction is non-spontaneous. E°cell = E°cathode - E°anode.

In a galvanic cell, oxidation occurs at the anode (negative electrode), while reduction occurs at the cathode (positive electrode).

When E°cell is negative, ΔG° = -nFE°cell will be positive, indicating a non-spontaneous reaction under standard conditions.

Rusting of iron is a corrosion process (galvanic corrosion) and not a direct application like electroplating, electrolysis, or electrorefining.

F = N_A × e = 6.022 × 10²³ × 1.602 × 10⁻¹⁹ C = 96485 C/mol, which equals Avogadro's number times the charge of one electron.

Potassium (K) has the most negative standard reduction potential and is most easily oxidized among the given options. The order of ease of oxidation is K > Cu > Ag > Au.

Negative E°cell indicates non-spontaneous reaction with positive ΔG°. The relationship is ΔG° = -nFE°cell.

Maximum EMF = E°cathode - E°anode = 0.80 - (-0.76) = 1.56 V for Zn-Ag cell.

Conductivity (κ) = concentration × molar conductivity. Upon dilution, concentration decreases faster than molar conductivity increases.

At cathode: Na⁺ + e⁻ → Na (reduction). At anode: 2Cl⁻ → Cl₂ + 2e⁻ (oxidation).

Anode undergoes oxidation (Zn → Zn²⁺ + 2e⁻), losing mass. Cathode undergoes reduction (Cu²⁺ + 2e⁻ → Cu), gaining mass.