Misconception 1: "The anode is always negative"

Incorrect. The anode is negative ONLY in a galvanic (voltaic) cell. In an electrolytic cell, the anode is connected to the POSITIVE terminal of the external battery. The ONLY thing that is universal: oxidation occurs at the anode (always).

Misconception 2: "More positive E° means stronger reducing agent"

Incorrect. More POSITIVE E° means stronger OXIDIZING agent (greater tendency to gain electrons/get reduced). More NEGATIVE E° means stronger reducing agent (greater tendency to lose electrons/get oxidized). Li (E° = −3.04 V) is the strongest reducing agent; $F_{2}$ (E° = +2.87 V) is the strongest oxidizing agent.

Misconception 3: "The Nernst equation constant is 0.0591 or 0.059"

Clarification. The exact value is (2.303 × 8.314 × 298)/96485 = 0.05916 V. NEET uses 0.0592 (rounded). Some books use 0.059 or 0.0591 — all are acceptable approximations. Don't lose marks over this rounding; use whatever value the question provides.

Misconception 4: "Weak electrolytes follow the Debye-Hückel-Onsager equation"

Incorrect. The equation Λm = Λ°m − A√C applies to STRONG electrolytes (KCl, NaCl, HCl) which are fully ionized. Weak electrolytes ($CH_{3}COOH$, $NH_{4}OH$) do NOT follow this linear relationship; their Λm vs. √C curve is non-linear and steeply rises at low C.

Misconception 5: "A fuel cell runs out like a battery"

Incorrect. A battery stores a fixed amount of chemical energy and depletes over time. A fuel cell works as long as fuel ($H_{2}$) is continuously supplied — it doesn't run out. It's more like an engine than a battery; fuel in, electricity out, water as by-product.

Misconception 6: "In electrolysis of aqueous NaCl, Na is deposited at cathode"

Incorrect. In aqueous NaCl, water molecules are preferentially reduced at the cathode (2$H_{2}$O + 2$e^{-}$ → $H_{2}$ + 2$OH^{-}$) rather than $Na^{+}$ ($Na^{+}$ + $e^{-}$ → Na), because the reduction potential of water (−0.83 V) is less negative than $Na^{+}$/Na (−2.71 V). Na metal is only obtained from electrolysis of MOLTEN NaCl (no water present).

Misconception 7: "E° = 0 means no current flows"

Clarification. E°cell = 0 means standard conditions show no net driving force. BUT this could be a concentration cell (same electrodes, different concentrations) where a non-zero EMF still exists due to concentration difference. E = 0 (not E°) means the system is at equilibrium.