Which of the following will not dissolve in a hot mixture of NaOH and H2O2? — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Fe(OH)3 does not form soluble complexes with NaOH or get oxidized by H2O2 to a soluble species, unlike Cr(OH)3 (forms CrO4^2-), Al(OH)3 (forms [Al(OH)4]^-), and Zn(OH)2 (forms [Zn(OH)4]^2-).