Question

When aluminium hydroxide is reacted with excess sodium hydroxide, the soluble amphoteric compound is formed. Mark the correct formula.

• A. ${\left[{Al\left(OH\right)}_4\right]}^{-}$
• B. ${\left[{Al\left(OH\right)}_5\right]}^{2-}$
• C. ${\left[{Al\left(OH\right)}_6\right]}^{3-}$
• D. ${\left[{Al\left(OH\right)}_7\right]}^{4-}$

Answer 1

The correct option is A ${\left[{Al\left(OH\right)}_4\right]}^{-}$

$Al(OH{)}_3+NaOH\to N{a}^{+}[Al(OH{)}_4{]}^{-}$

Aluminium hydroxide when reacted with excess sodium hydroxide, the soluble amphoteric compound formed is sodium tetra hydroxoaluminate (III).