Which of the following lanthanoid ions acts as a strong reducing agent by breaking its highly stable — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Europium ($Eu^{2+}$, $4f^7$) and Ytterbium ($Yb^{2+}$, $4f^{14}$) exhibit anomalous $+2$ states due to exchange energy stability. However, they willingly give up an electron to achieve the thermodynamically favored $+3$ state in water, acting as strong reductants.