Out of the following five elements, how many undergo disproportionation when reacted with an alkalin — Redox Reactions and Volumetric Analysis Chemistry Question

💡 Solution & Explanation

Chlorine, Phosphorus, Sulphur, and Iodine all disproportionate in base (e.g. $P_4 \rightarrow PH_3 + H_2PO_2^-$). Fluorine ($F_2$) is the sole exception. Being the most electronegative element, it only undergoes reduction to form $F^-$, while oxygen is forced to oxidize (forming $OF_2$ or $O_2$). Therefore, 4 elements disproportionate.