Certain basic radicals precipitate as hydroxides which are amphoteric in nature. Which of the follow — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Aluminum, Zinc, and Chromium hydroxides are amphoteric. When excess strong base (like NaOH) is added, they dissolve to form their respective soluble hydroxo-complexes: tetrahydroxoaluminate ($[Al(OH)_4]^-$), tetrahydroxozincate ($[Zn(OH)_4]^{2-}$), and tetrahydroxochromate ($[Cr(OH)_4]^-$). Iron(III) hydroxide ($Fe(OH)_3$) is strictly basic and remains as a reddish-brown precipitate in excess NaOH.