Chapter 6, Problem 32A

Summary Introduction

Introduction :

Solutions are homogeneous mixtures formed when a solute is dissolved in a solvent. There are two components in a solution- solvent and solute. The solvent is a substance in which another substance is dissolved. A solute is a substance that is dissolved in the solvent.

Answer to Problem 32A

Correct answer :

The correct answer is option (A) a base.

Explanation of Solution

Explanation/justification for the correct answer :

Option (A) a base. The substances that release hydroxide ions (OH^-) when dissolved in water are called bases. The more hydroxide ions a substance releases, the more basic is the solution. Sodium Hydroxide (NaOH) is a common base that breaks up in water to release sodium ions (Na⁺) and hydroxide ions (OH^-). So, the correct answer is option (A).

Explanation for incorrect answer :

Option (B) an acid. When a substance that contains hydrogen is dissolved in water, it may release a hydrogen ion (H⁺) because it is attached to the negatively charged oxygen atoms in water. Substances that release hydrogen ions when dissolved in water are called acids. The more hydrogen ions a substance releases, the more acidic is the solution. So, this is an incorrect option.

Option (C) a buffer. pH is the measure of concentration of hydrogen ions (H⁺) in a solution. Buffers are mixtures that react with acids and bases to keep the pH within a specific range. In cells, buffers keep the pH at 6.5-7.5. So, this is an incorrect answer.

Option (D) salt. A salt is an ionic compound formed by the reaction of an acid with a base. A salt consists of the positive ion (cation) of a base and the negative ion (anion) of an acid. Hence, this is an incorrect answer.