Question

If NaOH is added to an aqueous solution of Al3+ ions, a white precipitate appears and on adding excess of NaOH, the precipitate dissolves. In the solution, aluminium exists in the :

• A. Anionic part
• B. Cationic part
• C. Both in anionic and cationic part
• D. colloidal form

Answer 1

Answer: (A)

Anionic part

Answer 2

Al3+ + 4OH– (from NaOH) $\longrightarrow$[Al(OH)4]–

So aluminium exists in the anionic part