Question

Which of the following is an amphoteric hydroxide ?

• A. $Mg(OH)_2$
• B. $Be(OH)_2$
• C. $Sr(OH)_2$
• D. $Ca(OH)_2$

Answer 1

The Correct Option is B

 An amphoteric hydroxide is a hydroxide that can react both as an acid and as a base. To determine which of the given hydroxides is amphoteric, we need to understand the behavior of the hydroxides in chemical reactions:

1. \(Mg(OH)_2\):
   • Magnesium hydroxide is primarily a basic hydroxide. It is insoluble in water and acts as a base in the presence of acids.
   • It does not exhibit amphoteric behavior. Therefore, it is not an amphoteric hydroxide.
2. \(Be(OH)_2\):
   • Beryllium hydroxide is known to be amphoteric.
   • It can react with acids to form salts, like a base, and with strong bases to form beryllate ions, like an acid:
     • Reaction with acids (acting as a base):
     • Reaction with bases (acting as an acid):
3. \(Sr(OH)_2\):
   • Strontium hydroxide is a strong base. It completely dissociates in water and shows strong basicity.
   • It does not exhibit amphoteric behavior.
4. \(Ca(OH)_2\):
   • Calcium hydroxide, also known as slaked lime, is a moderately strong base.
   • Like magnesium hydroxide, it does not show amphoteric behavior and primarily acts as a base.

Based on the properties discussed, \(Be(OH)_2\) is the only compound among the options that is amphoteric. Therefore, the correct answer is \(Be(OH)_2\).