An inorganic cation has been precipitated from water by the addition of NaOH. When we find that the precipitate may be redissolved upon the addition of NaOH or dilute `HNO_3` , we may conclude that the precipitate was

Options

A. amphoteric
B. colloidal
C. amorphous
D. anthropomorphic

Answer

A

Explanation

This precipitate reacts with acid or base and therefore , is amphoteric . It could be aluminium hydroxide.
`Al(OH)_3 + 3H^(+) to Al^( + + +) + 3H_2O`
`Al(OH)_3 + OH^(-) to Al(OH)_4`