Question 1: Define a metal hydroxide and describe its general chemical formula.

Answer: A metal hydroxide is an ionic compound consisting of a metal cation and hydroxide anions, with the general formula MOH, where M represents a metal ion.

Question 2: Explain how metal hydroxides can be used to neutralise acids in environmental applications.

Answer: Metal hydroxides react with acids to produce salt and water, neutralising acidity. For example, aluminium hydroxide neutralises sulphuric acid in wastewater treatment.

Question 1: Calculate the number of moles of aluminium hydroxide (Al(OH)₃) required to neutralise 0.5 moles of sulphuric acid (H₂SO₄). Use the reaction: 2Al(OH)₃ + 3H₂SO₄ → Al₂(SO₄)₃ + 6H₂O.

Answer: 0.333 moles

Question 1: Describe a safe experimental procedure to test for the presence of metal hydroxide ions in a solution. Include safety precautions.

Answer: Add a few drops of dilute ammonium chloride solution to the sample, then gently warm. The formation of ammonia gas indicates the presence of metal hydroxide ions. Safety precautions include wearing gloves and eye protection, ensuring good ventilation, and handling chemicals carefully.

Question 1: A solution is tested with litmus paper and turns blue. It also reacts with dilute acid to produce salt and water. What can you deduce about the solution's composition and the metal hydroxide's role in renewable energy storage?

Answer: The solution contains metal hydroxide ions, making it alkaline. In renewable energy storage, metal hydroxides can act as charge carriers in batteries or capacitors, helping to stabilise charge and neutralise acids in energy systems.

Question 1: Explain the significance of metal hydroxides in the development of sustainable energy storage solutions. Include examples of specific metal hydroxides and their applications.

Answer: Metal hydroxides are vital in sustainable energy storage because they can undergo reversible reactions, storing and releasing energy efficiently. For example, nickel hydroxide is used in rechargeable nickel-metal hydride batteries, which are common in electric vehicles. Their chemical stability and capacity for charge transfer make them suitable for large-scale energy storage, reducing reliance on fossil fuels.

Question 1: Describe how metal hydroxides are used in the treatment of industrial wastewater from renewable energy plants, and explain why their chemical properties are suitable for this purpose.

Answer: Metal hydroxides such as aluminium hydroxide are used to neutralise acidic wastewater, removing sulphur compounds and other pollutants. Their ability to react with acids and form insoluble salts helps in pollutant removal, ensuring environmentally safe discharge.

Question 2: Considering the role of metal hydroxides in energy storage, suggest how advancements in this area could impact the future of renewable energy infrastructure.

Answer: Advancements in metal hydroxide-based energy storage could lead to more efficient, durable, and cost-effective batteries, enabling better storage of intermittent renewable sources like solar and wind. This would improve grid stability, reduce reliance on fossil fuels, and accelerate the transition to sustainable energy systems.