Electroplating & Electrolysis Calculator

Electrolysis and Faraday's Laws Guide

What's the key thing to understand about Faraday's Laws of Electrolysis?

First law: the mass deposited is proportional to the charge passed. Second law: for the same charge, masses deposited are proportional to molar mass/charge number. Combined formula: m = (I × t × M) / (n × F). Where m = mass (g), I = current (A), t = time (s), M = molar mass (g/mol), n = number of electrons transferred per ion, F = Faraday constant (96,485 C/mol). Example: copper deposition (Cu²⁺ + 2e⁻ → Cu, n=2, M=63.5 g/mol) at 2A for 1 hour: m = (2 × 3600 × 63.5)/(2 × 96485) = 2.38g.

What's the key thing to understand about Electroplating Applications?

Electroplating deposits a thin metal layer onto a conducting surface. The object to be plated is the cathode (negative electrode). The plating metal or an inert electrode is the anode. The electrolyte contains ions of the plating metal. Uses: chromium plating (decorative and corrosion protection), gold plating (electronics, jewellery), silver plating (cutlery), zinc galvanising (steel protection), copper interconnects in PCB manufacture. Thickness control: precisely calculated current × time control (via Faraday's laws of electrolysis) allows platers to deposit a specified mass and thickness of metal reliably, since the amount deposited is directly proportional to the total charge passed (current × time) and inversely related to the ion's charge.

What's the key thing to understand about Products of Electrolysis?

At the cathode (reduction): positive ions gain electrons. Metals are deposited from metal salt solutions. From dilute H₂SO₄: H₂ gas produced (H⁺ + e⁻ → ½H₂). At the anode (oxidation): negative ions or water are oxidised. Chloride ions: Cl⁻ → ½Cl₂ + e⁻ (concentrated chloride). Sulphate ions in dilute H₂SO₄: water oxidised → O₂ + H⁺ + e⁻. Metal anodes dissolve: Cu → Cu²⁺ + 2e⁻ (used in copper refining where impure copper anode dissolves and pure copper deposits at cathode).

What do I need to know about Electrolysis in Industry?

Chlor-alkali industry: electrolysis of brine (NaCl solution) produces chlorine (Cl₂), hydrogen (H₂), and sodium hydroxide (NaOH). The Downs process: electrolysis of molten NaCl produces sodium metal and chlorine — the only commercial route to sodium metal. Aluminium production: electrolysis of aluminium oxide dissolved in cryolite — requires enormous electrical energy (approximately 14,000 kWh per tonne of aluminium — the reason aluminium recycling is so energy-efficient by comparison). Hydrogen production by water electrolysis is a growing industrial application too, particularly for 'green hydrogen' where the electricity comes from renewable sources — splitting water into hydrogen and oxygen gas at the electrodes, with the hydrogen used as a fuel or industrial feedstock.