<p>(a) (i) Write the number of unpaired electrons in&nbsp;<span class="equation">\(Cr^{3+}. \)</span>&nbsp;(Atomic number of Cr = 24)​​​​​​​</p>

<p>(ii) Complete the reaction mentioning all the products formed:</p>

<p><span class="equation">\(Cr_2O^{2-}_7+3H_2S+8H^+\to\)</span></p>

<p>(b) Account for the following</p>

<p>(i)&nbsp;<span class="equation">\(Mn^{2+}\)</span>&nbsp;is more stable than&nbsp;<span class="equation">\(Fe^{2+}\)</span>&nbsp;towards oxidation to +3 state.</p>

<p>(ii) Copper has exceptionally positive&nbsp;<span class="equation">\(E^0_{M^{2+}/M}\)</span></p>

<p>(iii)&nbsp;<span class="equation">\(Eu^{2+}\)</span>&nbsp;with electronic configuration [Xe} 4<span class="equation">\(f^76s^2\)</span>&nbsp;is a strong reducing agent.​​​​​​​</p>