Redox: แบบฝึกหัด

Which statement correctly describes an oxidation reaction according to the transfer of oxygen?

In the chemical reaction: \( 2Fe + 3Cl_2 \rightarrow 2FeCl_3 \), which species is being oxidized and what is the reason?

When an unknown liquid X is added to a solution of aqueous potassium iodide, the solution turns from colorless to brown. Which statement about liquid X is correct?

What is the oxidation number of iron in iron(III) oxide, \(Fe_2O_3\)?

When acidified aqueous potassium manganate(VII) is used to test for sulfite ions, \(SO_3^{2-}\), the purple color disappears. Which statement correctly describes the role of the sulfite ions?

Define oxidation and reduction in terms of the gain or loss of oxygen atoms.

In the reaction \(2\text{Fe} + 3\text{Cl}_2 \rightarrow 2\text{FeCl}_3\), identify which species is oxidised and explain your answer in terms of electron transfer.

Manganese(IV) oxide reacts with hot concentrated hydrochloric acid to produce manganese(II) chloride, chlorine gas, and water.

(a) State the oxidation number of manganese in \(\text{MnO}_2\) and in \(\text{MnCl}_2\).
(b) Identify the oxidizing agent in this reaction, and explain your choice in terms of changes in oxidation number.

Redox reactions involve simultaneous oxidation and reduction. Consider the following reaction between copper(II) oxide and hydrogen gas:

\(\text{CuO(s)} + \text{H}_2\text{(g)} \rightarrow \text{Cu(s)} + \text{H}_2\text{O(g)}\)

(a) Define oxidation in terms of oxygen gain or loss.
(b) Identify the substance that is reduced in this reaction.
(c) Explain your answer to part (b) by referring to the movement of oxygen.

Redox reactions can be defined in terms of electron transfer and oxidation numbers. Consider the reaction between zinc metal and aqueous copper(II) sulfate:

\(\text{Zn(s)} + \text{CuSO}_4\text{(aq)} \rightarrow \text{ZnSO}_4\text{(aq)} + \text{Cu(s)}\)

(a) Write the ionic half-equation for the oxidation of zinc.
(b) State the oxidation number of sulfur in the sulfate ion (\(\text{SO}_4^{2-}\)). Show your working.
(c) Identify the oxidising agent in this reaction and explain your choice in terms of electron transfer.