23) Which of the following processes is easy to occur? a) \( \mathrm{V}_{2} \mathrm{O}_{5} \rightarrow \mathrm{V}_{2} \mathrm{O}_{3} \) b) \( \mathrm{KMnO}_{4} \rightarrow \mathrm{Mn}_{2} \mathrm{O}_{3} \) c) \( \mathrm{TiCl}_{2} \rightarrow \mathrm{TiCl}_{4} \) d) \( \mathrm{Fe}_{2} \mathrm{O}_{3} \rightarrow \mathrm{FeSO}_{4} \)

To determine which of the given processes is easy to occur, we need to consider the oxidation states and the stability of the compounds involved in each reaction. a) \( \mathrm{V}_{2} \mathrm{O}_{5} \rightarrow \mathrm{V}_{2} \mathrm{O}_{3} \): This reaction involves the reduction of vanadium from a +5 oxidation state in \( \mathrm{V}_{2} \mathrm{O}_{5} \) to a +3 oxidation state in \( \mathrm{V}_{2} \mathrm{O}_{3} \). This is a common reduction process and can occur under suitable conditions. b) \( \mathrm{KMnO}_{4} \rightarrow \mathrm{Mn}_{2} \mathrm{O}_{3} \): This reaction involves the reduction of manganese from a +7 oxidation state in \( \mathrm{KMnO}_{4} \) to a +3 oxidation state in \( \mathrm{Mn}_{2} \mathrm{O}_{3} \). This is a significant reduction and typically requires strong reducing agents or specific conditions. c) \( \mathrm{TiCl}_{2} \rightarrow \mathrm{TiCl}_{4} \): This reaction involves the oxidation of titanium from a +2 oxidation state in \( \mathrm{TiCl}_{2} \) to a +4 oxidation state in \( \mathrm{TiCl}_{4} \). This is an oxidation process that can occur readily, especially in the presence of chlorine gas. d) \( \mathrm{Fe}_{2} \mathrm{O}_{3} \rightarrow \mathrm{FeSO}_{4} \): This reaction involves the conversion of iron(III) oxide to iron(II) sulfate. This is not a straightforward reaction and typically requires specific conditions, such as the presence of sulfuric acid. Considering the above analyses, the easiest process to occur among the options is: **c) \( \mathrm{TiCl}_{2} \rightarrow \mathrm{TiCl}_{4} \)** This reaction is relatively straightforward and can occur under standard conditions with the presence of chlorine.