--- title: "Electrolysis of Solutions and Getting Reactive Metals Out of Ores" description: "Predict products for common aqueous salt solutions using inert electrodes. Explain how reactivity affects industrial metal extraction, how molten cryolite is used in aluminium production, and why recy" canonical: https://lightmysky.com/learn/science/electrolysis-of-solutions-and-getting-reactive-metals-out-of-ores-mt_l-t_JxRR7f source: https://lightmysky.com/learn/science/electrolysis-of-solutions-and-getting-reactive-metals-out-of-ores-mt_l-t_JxRR7f.md retrieved: 2026-11-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Electrolysis of Solutions and Getting Reactive Metals Out of Ores Predict products for common aqueous salt solutions using inert electrodes. Explain how reactivity affects industrial metal extraction, how molten cryolite is used in aluminium production, and why recycling aluminium saves energy. Subject: Science · Area: Matter & Materials · Ages 15 to 16 Page: https://lightmysky.com/learn/science/electrolysis-of-solutions-and-getting-reactive-metals-out-of-ores-mt_l-t_JxRR7f ## Ready when they can - Predicts electrode products for the common aqueous salt solutions taught here, using inert electrodes and the stated concentration conditions - Explains why aluminium is extracted by electrolysis while iron is reduced with carbon - Explains why cryolite is added to the aluminium oxide and what it saves - Explains why recycling aluminium uses far less energy than extracting new aluminium from ore ## Lesson: Solutions, ores and who wins A melt has mobile ions. An aqueous solution also contains water, which can react at the electrodes. For the salt solutions here, assume inert electrodes and a direct-current supply. At the cathode, a metal less reactive than hydrogen is deposited. If the metal is more reactive than hydrogen, hydrogen forms from water instead. Copper is below hydrogen in reactivity; sodium and aluminium are above it. At an inert anode, sulfate solutions give oxygen from water. Concentrated chloride, bromide or iodide solutions give chlorine, bromine or iodine. These rules do not cover every solution or electrode. In a separated brine cell, hydrogen forms at the cathode, chlorine at the anode and sodium hydroxide solution is produced. Sodium ions remain dissolved. Keeping the products apart prevents them reacting with each other. Iron is below carbon in the reactivity series, so carbon-based reduction can extract it from its oxide. In a blast furnace, carbon monoxide made from coke does most of this reduction. Aluminium is above carbon, so carbon reduction is not the usual industrial extraction method. Industry uses electrolysis of purified aluminium oxide dissolved in molten cryolite. Recycling aluminium reuses metal that has already been extracted. Scrap still needs collection, sorting, cleaning and melting. It does not need fresh ore to be mined and purified, or another extraction by electrolysis. Avoiding these stages explains why recycling aluminium uses far less energy than making new aluminium from ore. Pure aluminium oxide needs a very high temperature to melt. Factories instead dissolve it in molten cryolite. The mixture stays liquid at a lower temperature than pure aluminium oxide, reducing the energy needed to keep it molten. The dissolved ions can move to the electrodes. Electrolysis still needs a large electrical energy input; cryolite does not replace that step. *(drawing: The molten mixture contains mobile ions and stays liquid below the melting point of pure aluminium oxide.)* **Recap.** For the cases here, water competes at inert electrodes. Aluminium extraction uses a molten cryolite mixture. Recycling avoids extracting fresh aluminium from ore. *This lesson, question bank and flashcards were written for this dataset.* ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Electrolysis: Half Equations at the Electrodes](https://lightmysky.com/learn/science/electrolysis-half-equations-at-the-electrodes-mt_6FvxaD8wTY) - [The Reactivity Series](https://lightmysky.com/learn/science/the-reactivity-series-mt_zsYW61cn_q) ## Optional connections - [Finite Resources & Recycling](https://lightmysky.com/learn/science/finite-resources-and-recycling-mt_0e5rZxbAeR)