Chapter: Chemical Kinetics· Chemistry

Distinguish between order and molecularity of a reaction. Write gases liberated at cathode and anode during electrolysis of aqueous NaCl solution. Write two uses of neon.

Q.29 Distinguish between order and molecularity of a reaction. Write gases liberated at cathode and anode during electrolysis of aqueous NaCl solution. Write two uses of neon.

Doubtly Asked 29 Oct 2026 Board exam · July 2024 hsc 12th Save WhatsApp Report

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Order	Molecularity
Sum of the powers of the concentration terms in the experimental rate law.	Number of reactant molecules (atoms/ions) taking part in an elementary step.
Determined experimentally.	A theoretical concept, found from the mechanism.
Can be zero, a whole number or a fraction.	Always a whole number (1, 2 or 3), never zero or fractional.
Applies to the overall reaction.	Applies to each elementary step; meaningless for a complex overall reaction.

Electrolysis of aqueous NaCl: hydrogen gas (H₂) is liberated at the cathode (2H₂O + 2e⁻ → H₂ + 2OH⁻) and chlorine gas (Cl₂) at the anode (2Cl⁻ → Cl₂ + 2e⁻); NaOH remains in solution.

Uses of neon (any two): in neon discharge lamps and signs for advertisement (orange-red glow); in beacon/warning lights and fog lights; mixed with helium in protecting electrical instruments from high voltage and in voltage stabilisers.

Doubtly AI · 29 Oct 2026 AI-verified · Nov 2026 Report

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Distinguish between order and molecularity of a reaction. Write gases liberated at cathode and anode during electrolysis of aqueous NaCl solution. Write two uses of neon.

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