NCERT Class 9 Science — Chapter 2: Is matter around us pure?

mcqeasy

In the context of solution chemistry, the terms 'dilute' and 'concentrated' are:

Official previous-year question

Verified 1 Aug 2026.

Options

ADetermined by the density of the solvent.
BApplicable only to solid-in-liquid solutions.
CAbsolute values defined by IUPAC.
DComparative terms indicating the relative amount of solute.

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Solution

Correct Option

The correct option is

Comparative terms indicating the relative amount of solute.

Explanation

In chemistry, a solution is a homogeneous mixture composed of two or more substances: the solute (the substance dissolved) and the solvent (the dissolving medium). The term concentration refers to the amount of solute present in a given quantity of solvent or solution.

Option Analysis

Absolute values defined by IUPAC. is Incorrect: The terms "dilute" and "concentrated" are qualitative descriptions, not quantitative absolute values defined by IUPAC. There is no specific numerical threshold that separates a dilute solution from a concentrated one.
Comparative terms indicating the relative amount of solute. is Correct: These are comparative terms. A dilute solution contains a relatively small amount of solute dissolved in a large amount of solvent. Conversely, a concentrated solution contains a relatively large amount of solute. The distinction is relative rather than absolute.
Applicable only to solid-in-liquid solutions. is Incorrect: These terms are applicable to various types of solutions, including liquid-in-liquid (e.g., alcohol in water) and gas-in-liquid (e.g., ammonia in water), not just solid-in-liquid systems.
Determined by the density of the solvent. is Incorrect: While the concentration of a solution affects its density, the terms "dilute" and "concentrated" are defined by the ratio of solute to solvent, not by the density of the solvent itself.

Key Takeaway

Dilute and concentrated are relative, qualitative terms describing the proportion of solute within a solution; they do not represent fixed scientific constants or absolute values.

Your note

More from Chapter 2: Is matter around us pure?

With reference to 'Alloys', consider the following statements: 1. They are considered mixtures because they show the properties of their constituents. 2. They can be separated into their components by physical methods. 3. They have a fixed composition and cannot vary. Which of the statements given above is/are correct?

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Consider the following statements regarding the properties of metals: 1. They are generally brittle and non-ductile. 2. They are generally good conductors of heat and electricity. 3. They are sonorous. Which of the statements given above is/are correct?

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Consider the following statements about elements: 1. The majority of elements are solids. 2. Only two elements are in the gaseous state at room temperature. 3. Gallium and Cesium remain solid even at temperatures well above 303 K. Which of the statements given above is/are correct?

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In the classification of colloids, 'Cheese' and 'Butter' are examples of:

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Consider the following statements regarding the burning of wood: 1. It involves the conversion of wood into new substances like ash and smoke. 2. It is a physical change. 3. It is an irreversible process. Which of the statements given above is/are correct?

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Correct Option

The correct option is

Comparative terms indicating the relative amount of solute.

Explanation

Option Analysis

Absolute values defined by IUPAC. is Incorrect: The terms "dilute" and "concentrated" are qualitative descriptions, not quantitative absolute values defined by IUPAC. There is no specific numerical threshold that separates a dilute solution from a concentrated one.
Comparative terms indicating the relative amount of solute. is Correct: These are comparative terms. A dilute solution contains a relatively small amount of solute dissolved in a large amount of solvent. Conversely, a concentrated solution contains a relatively large amount of solute. The distinction is relative rather than absolute.
Applicable only to solid-in-liquid solutions. is Incorrect: These terms are applicable to various types of solutions, including liquid-in-liquid (e.g., alcohol in water) and gas-in-liquid (e.g., ammonia in water), not just solid-in-liquid systems.
Determined by the density of the solvent. is Incorrect: While the concentration of a solution affects its density, the terms "dilute" and "concentrated" are defined by the ratio of solute to solvent, not by the density of the solvent itself.

Key Takeaway

Dilute and concentrated are relative, qualitative terms describing the proportion of solute within a solution; they do not represent fixed scientific constants or absolute values.