Fe(OH)2 is precipitated from Fe(II) solutions as a while solid but turns dark green and then brown d — d and f Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: In the redox titration of oxalic acid with potassium permanganate (KMnO4), KMnO4 serves as the oxidizing agent. Step 2: The intensely purple-colored permanganate ions (MnO4^-) are reduced to colorless manganese(II) ions (Mn2+) as long as oxalic acid is present to react. Step 3: At the end-point, the very first excess drop of KMnO4 remains unreduced and imparts a permanent light pink color to the solution. Therefore, KMnO4 acts as its own indicator (self-indicator), matching option (a).