What is the product formed when bauxite ore is treated with sodium hydroxide?

What is the product formed when bauxite ore is treated with sodium hydroxide?
  1. Sodium meta aluminate
  2. Aluminium hydroxide
  3. Sodium aluminate
  4. Sodium hydrogen carbonate

Solution

Conc. sodium hydroxide. Bauxite ore is finely divided and heated under pressure with concentrated caustic soda solution at $150^{\circ} \mathrm{C}$ to obtain sodium meta-aluminate. The following reaction is as follows: $\underset{\text { Bauxite }}{\mathrm{Al}_{2} \mathrm{O}_{3} .2 \mathrm{H}_{2} \mathrm{O}+2 \mathrm{NaOH}} \stackrel{150^{0} \mathrm{C}}{\longrightarrow} 2 \mathrm{NaAlO}_{2}+\underset{\text { sodium meta aluminate }}{3 \mathrm{H}_{2} \mathrm{O}}$

Asked in: MHT CET 2020 (14 Oct Shift 1)

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