Prolonged heating is avoided during the preparation of ferrous ammonium sulphate to :

<p>Prolonged heating is avoided during the preparation of ferrous ammonium sulfate to <strong>prevent oxidation</strong>. Ferrous ammonium sulfate is a green crystalline solid that is used as a reducing agent in various chemical reactions. When heated, it can undergo oxidation to form ferric ammonium sulfate, which is a brown crystalline solid.</p> <p>Here is a chemical equation for the oxidation of ferrous ammonium sulfate:</p> $$\begin{equation} \ce{FeSO4(NH4)2SO4.6H2O + O2 -> Fe2(SO4)3(NH4)2SO4.12H2O} \end{equation}$$<p>As you can see, the oxidation of ferrous ammonium sulfate results in the formation of ferric ammonium sulfate, which is a brown crystalline solid. This is why prolonged heating is avoided during the preparation of ferrous ammonium sulfate.</p> <p>Here are the other options and why they are incorrect:</p> <ul> <li>Option A: Hydrolysis is the process of a chemical compound reacting with water. Ferrous ammonium sulfate is not hydrolyzed by water, so prolonged heating is not necessary to prevent hydrolysis.</li><br/> <li>Option B: Breaking is the process of a chemical compound being physically broken apart. Ferrous ammonium sulfate is not broken apart by heat, so prolonged heating is not necessary to prevent breaking.</li><br/> <li>Option D: Reduction is the process of a chemical compound gaining electrons. Ferrous ammonium sulfate is a reducing agent, so it is not reduced by heat.</li> </ul>