Aqueous ammonia is used instead of an aqueous | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) $Al(OH)_3$ is an amphoteric hydroxide. When $NaOH$ (a strong base) is added in excess,it reacts with $Al(OH)_3$ to form a soluble complex,$[Al(OH)

Vedclass · Accepted Answer

$NaOH$ forms $[Al(OH)_4]^-$ ions.

Vedclass · Answer

(B) $Al(OH)_3$ is an amphoteric hydroxide. When $NaOH$ (a strong base) is added in excess,it reacts with $Al(OH)_3$ to form a soluble complex,$[Al(OH)_4]^-$,which prevents the precipitation of $Al^{+3}$ ions. $Al(OH)_3 + OH^- \rightarrow [Al(OH)_4]^-$. Since aqueous ammonia is a weak base,it provides a limited concentration of $OH^-$ ions,which is sufficient to precipitate $Al(OH)_3$ but not strong enough to dissolve the precipitate by forming the complex.

Aqueous ammonia is used instead of an aqueous solution of $NaOH$ to precipitate $Al^{+3}$ ions as $Al(OH)_3$ because:

Similar Questions

$A$ solution is $0.1 \ M$ with respect to $AcOH$ and $0.2 \ M$ with respect to $AcONa$. What is the concentration of $Ac^-$? (Given $x = 0.2$)

Solubility of $AgCl$ in conc. $HCl$ is ...... than in water.

In which of the following,the solubility of $AgCl$ will be minimum?

The following equilibrium exists in an aqueous solution of hydrogen sulphide: $H_2S \rightleftharpoons H^{+} + HS^{-}$. If dilute $HCl$ is added to an aqueous solution of $H_2S$ without any change in temperature,what happens?

Addition of conc. $HCl$ to saturated $BaCl_2$ solution precipitates $BaCl_2$; because

Vedclass Test Series

Exam Paper Generator

Online Exam Module