Test: Important Chemical Compounds - 2 - Class 10 MCQ

Acids produce H⁺ ions when dissolved in water. These ions are essential to the acidic properties of the solution and play a significant role in various acid-base reactions.

When a base is dissolved in water, it produces OH^- ions. These hydroxide ions are responsible for the basic properties of the solution and are involved in neutralizing acids in chemical reactions.

A pH value of 7 indicates that the solution is neutral. The pH scale is a measure of the concentration of H⁺ ions in a solution. A pH of 7 signifies a neutral solution, where the concentration of H⁺ ions is balanced.

The strength of an acid or base can be estimated using a universal indicator by observing the color change of the indicator. Universal indicator is a mixture of several indicators that display different colors at different concentrations of H⁺ ions in the solution. This color change helps in determining whether the solution is acidic, basic, or neutral.

The general chemical equation for the reaction between a metallic oxide and an acid is Metallic oxide + Acid → Salt + Water. This reaction typically results in the formation of a salt and water. For example, when calcium oxide (CaO) reacts with hydrochloric acid (HCl), it produces calcium chloride (CaCl₂) and water (H₂O).

Metallic oxides are typically basic in nature, and when they react with bases, they usually do not undergo a reaction because both are basic. However, if a metallic oxide reacts with an acid, it forms a salt and water. The reaction given in the first option is similar to the reaction between an acid and a base, but not exactly applicable for a reaction between a metallic oxide and a base.

Therefore, under normal circumstances, metallic oxides do not react with bases.

However, if we consider amphoteric oxides (which can react with both acids and bases), they can react with a base to form a salt and water.

The correct answer that fits the context of amphoteric oxides would be:

Answer: 1 (Metallic Oxide + Base → Salt + Water)

This reaction is typical for amphoteric oxides like aluminum oxide (Al₂O₃) or zinc oxide (ZnO) reacting with a base. For example:

When ZnO reacts with sodium hydroxide (NaOH), the resulting product is sodium zinc oxide, represented by the chemical formula Na2ZnO2. This reaction demonstrates the basic nature of metallic oxides like ZnO when they react with bases to form salts and water.

When an acid reacts with a metal carbonate, the chemical reaction results in the formation of salt, carbon dioxide, and water. This reaction is a characteristic property of acids, where the carbonate compound reacts with the acid to produce these specific products. The evolution of carbon dioxide gas during this reaction is often observable as bubbles, indicating the release of the gas.