Oxidation, reduction and redox equations: แบบฝึกหัด

What is the oxidation state of chromium in the compound potassium dichromate, \(K_2Cr_2O_7\)?

The oxidation of ethanedioate ions (oxalate, \(C_2O_4^{2-}\)) and the reduction of manganate(VII) ions (permanganate, \(MnO_4^-\) in acidic conditions are represented by the following half-equations:

\(C_2O_4^{2-} \rightarrow 2CO_2 + 2e^-\)

\(MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O\)

Combine these two half-equations to form the overall balanced redox equation using the smallest whole number coefficients. What is the coefficient for \(H_2O\)?

Which of the following is the correctly balanced half-equation for the oxidation of sulfite ions (\(SO_3^{2-}\)) to sulfate ions (\(SO_4^{2-}\)) in acidic solution?

Calculate the average oxidation state of sulfur in the thiosulfate ion, \(S_2O_3^{2-}\).

In the reaction below, which species acts as the reducing agent?

\(SO_2(g) + 2H_2S(g) \rightarrow 3S(s) + 2H_2O(l)\)

Consider the redox reaction: \(\text{Zn}(\text{s}) + \text{Cu}^{2+}(\text{aq}) \rightarrow \text{Zn}^{2+}(\text{aq}) + \text{Cu}(\text{s})\). Identify the oxidising agent and the reducing agent, and state the half-equation for the process occurring at the zinc electrode.

The half-equation for the reduction of dichromate(VI) ions to chromium(III) ions in acid is \(\text{Cr}_2\text{O}_7^{2-} + 14\text{H}^+ + 6\text{e}^- \rightarrow 2\text{Cr}^{3+} + 7\text{H}_2\text{O}\). Combine this with the oxidation of \(\text{Fe}^{2+}\) to \(\text{Fe}^{3+}\) to derive the overall balanced ionic equation for the reaction.

Write a balanced half-equation for the reduction of chlorine gas, \(\text{Cl}_2\), in aqueous solution.

Vanadium exhibits several stable oxidation states in aqueous solution, visible as different colours: \( \text{V}(\text{V}) \) (yellow), \( \text{V}(\text{IV}) \) (blue), \( \text{V}(\text{III}) \) (green), and \( \text{V}(\text{II}) \) (violet). The reduction is typically carried out using zinc metal in acidic solution.

Chlorine gas reacts with cold, dilute aqueous sodium hydroxide solution. This reaction involves the oxidation and reduction of the same element, Chlorine.