AQA Chemistry A-level 3.2.6 Reaction of Metal Aqua Ions PDF

AQA Chemistry A-level 3.2.6: Reaction of Metal Aqua Ions Detailed Notes This work by PMT Education is licensed under https://bit.ly/pmt-cc https://bit.ly/pmt-edu-cc CC BY-NC-ND 4.0...

AQA Chemistry A-level 3.2.6: Reaction of Metal Aqua Ions Detailed Notes This work by PMT Education is licensed under https://bit.ly/pmt-cc https://bit.ly/pmt-edu-cc CC BY-NC-ND 4.0 https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc 3.2.6.1 - Ions in aqueous solution Metal ions become h ​ ydrated​ in water with H​ 2​O ligands around the central metal ion. The reaction of four major metal aqua ions have to be known for this A-Level specification; i​ron(II), copper(II), iron(III) and aluminium​. They form c ​ oloured precipitates​ that can be used to identify the metal ion present. Acid-base Properties When these ions are in solution, they are a​ cidic​. Metal ions that form 2 ​ +​​ ions​, iron(II) and +​ copper(II), form weaker acidic solutions than those that form 3 ​ ​ ions​, Iron(III) and aluminium. +​ -​ Therefore the 3​ ions dissociate more and have a greater attractive power to OH​ , basic ions, ie. they are stronger acids. Reactions with NaOH ​ eutralisation ​reaction Solutions of these metal ions r​eact as acids​ with sodium hydroxide in a n to form a salt and water. Example: The precipitates formed are coloured, indicated by the colour of the text. Aluminium forms a white precipitate. It is easiest to remember the formulas of the precipitates by remembering that the number of OH​-​ substituted is the same as the value of the charge on the initial ion. These reactions h ​ ydrolyse​ the metal ions to form the coloured precipitates. https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Amphoteric Salts ​ luminium salt ​can act as an acid or a base meaning it is a The a ​ mphoteric​. This means that if sodium hydroxide is added in e​ xcess​, the salt acts as an acid and is hydrolysed further. Example: Reactions with NH​3 Solutions of these metal ions react in a similar way with a ​ queous ammonia​ to form a salt and ammonium ions. Example: When ammonia is added in e ​ xcess​ to these precipitates, the c ​ opper(II) salt undergoes ligand substitution​ to form a​deep blue​ solution. Example: https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc Reactions with Na2CO​3 Solutions of these metal 2+​​ ions react with s ​ odium carbonate as acids​, forming i​nsoluble carbonates ​and water. Example: +​ Solutions of the metal 3​ ions act as​stronger acids​ meaning they react with sodium carbonate to form a salt, water and carbon dioxide. Example: Reactions with Cl​-​ ions All metal aqua ions undergo​ligand substitution​ reactions to form t​etrahedral ions with four Cl​-​ ligands​. This occurs when they react with concentrated hydrochloric acid. Example: https://bit.ly/pmt-cc https://bit.ly/pmt-edu https://bit.ly/pmt-cc