Question

The pair of amphoteric hydroxides is:

• A. $\mathrm{Al}{\left[\mathrm{OH}\right]}_3,\mathrm{LiOH}$
• B. $\mathrm{Be}{\left[\mathrm{OH}\right]}_2,\mathrm{Mg}{\left[\mathrm{OH}\right]}_2$
• C. $\mathrm{B}{\left[\mathrm{OH}\right]}_2,\mathrm{Be}{\left[\mathrm{OH}\right]}_2$
• D. $\mathrm{Be}{\left[\mathrm{OH}\right]}_2$$,$$\mathrm{Zn}{\left[\mathrm{OH}\right]}_2$

Answer 1

The correct option is D

$\mathrm{Be}{\left[\mathrm{OH}\right]}_2$$,$$\mathrm{Zn}{\left[\mathrm{OH}\right]}_2$

Explanation for the correct option:

[D]$\mathrm{Be}{\left[\mathrm{OH}\right]}_2$$,$$\mathrm{Zn}{\left[\mathrm{OH}\right]}_2$

• Metals give Basic hydroxides whereas, non-metals give Acidic hydroxides.
• Metals with electropositive nature give Amphoteric hydroxides which act as both acid and a base.
• $\mathrm{Be},\mathrm{Zn}$are both metals with electropositive nature.
• So, they will form Amphoteric oxides which act as the base with acid and as a base with acid causing neutralization.

So, option[D] is correct.

Explanation for the Incorrect options:

[A]$\mathrm{Al}{\left[\mathrm{OH}\right]}_3,\mathrm{LiOH}$

• Here, $\mathrm{Al}$ [Aluminum] metal forms Amphoteric hydroxide due to its electropositive nature.
• But,$\mathrm{Li}$ [Lithium] acts as a metal forming the Basic hydroxide.
• Only one of them is amphoteric.

So, option[A] is incorrect.

[B]$\mathrm{Be}{\left[\mathrm{OH}\right]}_2,\mathrm{Mg}{\left[\mathrm{OH}\right]}_2$

• Here, $\mathrm{Be}$[Beryllium] metal forms Amphoteric hydroxide due to its electropositive nature.
• But, $\mathrm{Mg}$[Magnesium] acts as a metal forming the Basic hydroxide.
• Only one of them is amphoteric.

So, option[B] is incorrect.

[C]$\mathrm{B}{\left[\mathrm{OH}\right]}_2,\mathrm{Be}{\left[\mathrm{OH}\right]}_2$

• Here, $\mathrm{Be}$[Beryllium] metal forms Amphoteric hydroxide due to its electropositive nature.
• But, $\mathrm{B}$[Boron] acts as a non-metal forming the Acidic hydroxide.
• Only one of them is amphoteric.

So, option[C] is incorrect.

Hence, option[D] has both Amphoteric hydroxides.