Variable oxidation states (A-level only) (3.2.5.5) | AQA A-level Chemistry - (7405)

3.2.5.5 Variable oxidation states (A-level only)

Content	Opportunities for skills development
$Transition elements show variable oxidation states. Vanadium species in oxidation states IV, III and II are formed by the reduction of vanadate(V) ions by zinc in acidic solution. The redox potential for a transition metal ion changing from a higher to a lower oxidation state is influenced by pH and by the ligand. The reduction of [Ag(NH₃)₂]⁺ (Tollens’ reagent) to metallic silver is used to distinguish between aldehydes and ketones. The redox titrations of Fe²⁺ and C₂O₄²⁻ with MnO₄⁻ Students should be able to: perform calculations for these titrations and similar redox reactions.$	$AT d and k PS 1.2 Students could reduce vanadate(V) with zinc in acidic solution. AT b, d and k PS 4.1 Students could carry out test-tube reactions of Tollens' reagent to distinguish aldehydes and ketones. AT a, d, e and k PS 2.3, 3.2 and 3.3 Students could carry out redox titrations. Examples include, finding:$

Content

Opportunities for skills development

Transition elements show variable oxidation states. Vanadium species in oxidation states IV, III and II are formed by the reduction of vanadate(V) ions by zinc in acidic solution. The redox potential for a transition metal ion changing from a higher to a lower oxidation state is influenced by pH and by the ligand. The reduction of [Ag(NH₃)₂]⁺ (Tollens’ reagent) to metallic silver is used to distinguish between aldehydes and ketones. The redox titrations of Fe²⁺ and C₂O₄²⁻ with MnO₄⁻ Students should be able to: perform calculations for these titrations and similar redox reactions.

AT d and k PS 1.2 Students could reduce vanadate(V) with zinc in acidic solution. AT b, d and k PS 4.1 Students could carry out test-tube reactions of Tollens' reagent to distinguish aldehydes and ketones. AT a, d, e and k PS 2.3, 3.2 and 3.3 Students could carry out redox titrations. Examples include, finding:

Variable oxidation states (A-level only)