Metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides. Amphoteric oxides include lead oxide and zinc oxide, among many others.

Amphoteric Metals:
Amphoteric metals are those metals that have the ability to react with both acids and bases. This means that they can act as both an acid and a base, depending on the reaction conditions. These metals are sometimes referred to as amphoteric oxides or hydroxides.

Examples of Amphoteric Metals:
Some common examples of amphoteric metals include aluminum (Al), zinc (Zn), tin (Sn), lead (Pb), and bismuth (Bi). These metals have the ability to form both acidic and basic oxides or hydroxides.

Reactions with Acids:
When an amphoteric metal reacts with an acid, it behaves as a base and accepts a proton (H+) from the acid. This results in the formation of a salt and the release of hydrogen gas (H2). The general equation for this reaction is:

Metal + Acid → Salt + Hydrogen gas

For example, when aluminum reacts with hydrochloric acid (HCl), aluminum chloride (AlCl3) is formed along with the release of hydrogen gas:

2Al + 6HCl → 2AlCl3 + 3H2

Reactions with Bases:
On the other hand, when an amphoteric metal reacts with a base, it behaves as an acid and donates a proton (H+) to the base. This leads to the formation of a salt and water. The general equation for this reaction is:

Metal + Base → Salt + Water

For instance, when zinc reacts with sodium hydroxide (NaOH), zincate ion (Zn(OH)4^2-) is formed along with water:

Zn + 2NaOH → Na2Zn(OH)4 + H2O

Conclusion:
In conclusion, metals that react with both acids and bases are called amphoteric metals. They have the ability to behave as both an acid and a base, depending on the reaction conditions. Examples of amphoteric metals include aluminum, zinc, tin, lead, and bismuth. The reactions of these metals with acids and bases result in the formation of salts and the release of hydrogen gas or water, depending on the reaction.

Option D