Chemistry Q133 – AP-EAMCET 2026

Home Chemistry Periodicity & ElementsQuestion #491

The oxide and hydroxide of which metal are amphoteric in nature?

Clue 1 of 3: Amphoteric Character

Amphoteric substances are those that can react with both acids and bases. This property is common for certain metal oxides and hydroxides.

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Step 1: Define Amphoteric Substances✦ Active

An amphoteric substance is a chemical species that has the ability to react both as an acid and as a base. In the context of metal oxides and hydroxides, this means they can neutralize both acidic and basic solutions.

💡 Teacher's Secret Hint

Remember that amphoteric behavior is an intermediate property between purely acidic (non-metal oxides) and purely basic (metal oxides).

Step 2: Analyze the Nature of Oxides and Hydroxides for Given Metals○ Expand

Let's examine the common behavior of oxides and hydroxides for the given options:

1. **Lithium (Li), Sodium (Na), and Magnesium (Mg):** These are alkali and alkaline earth metals. Their oxides ( ${Li}_{2} O$ , ${Na}_{2} O$ , $MgO$ ) and hydroxides ( $LiOH$ , $NaOH$ , ${Mg(OH)}_{2}$ ) are typically basic in nature. They readily react with acids but not with bases.

{Na}_{2} O (s) + 2 HCl (a q) \to 2 NaCl (a q) + H_{2} O (l)

💡 Teacher's Secret Hint

The basic character of oxides generally increases down a group and decreases across a period for metallic elements.

Step 3: Identify the Amphoteric Metal○ Expand

2. **Beryllium (Be):** Although Beryllium is an alkaline earth metal (Group 2), it exhibits unique properties due to its small size, high charge density, and strong polarizing power. This leads to its compounds having significant covalent character, and its oxide ( $BeO$ ) and hydroxide ( ${Be(OH)}_{2}$ ) are amphoteric.

Beryllium hydroxide reacts with both acids and strong bases:

Reaction with an acid (acting as a base):

{Be(OH)}_{2} (s) + 2 HCl (a q) \to {BeCl}_{2} (a q) + 2 H_{2} O (l)

Reaction with a strong base (acting as an acid):

{Be(OH)}_{2} (s) + 2 NaOH (a q) \to {Na}_{2} [{Be(OH)}_{4}] (a q)

Therefore, Beryllium is the metal whose oxide and hydroxide are amphoteric in nature.

💡 Teacher's Secret Hint

Beryllium's amphoteric nature is an example of anomalous behavior within its group, often linked to its diagonal relationship with aluminum, which also forms amphoteric oxides/hydroxides.

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Chemistry Question 133 – AP-EAMCET 2026

Clue 1 of 3: Amphoteric Character

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