Problem 11 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The aerosol is a kind of colloid in which:(a) solid is dispersed in gas (b) gas is dispersed in solid (c) gas is dispersed in liquid (d) liquid is dispersed in water

Step-by-Step Solution

Answer

(a) solid is dispersed in gas.

Step 1: Identify Keywords

First, identify the keywords in the question, such as "aerosol," "colloid," and "dispersed in." This will help understand what the question is asking for.

Step 2: Understand 'Aerosol' Definition

Recall the definition of "aerosol." An aerosol is a type of colloid where a dispersing phase and dispersed phase are involved. Specifically, in aerosols, the dispersed phase is usually solid or liquid particles, and the dispersing medium is a gas.

Step 3: Analyze Each Option

Examine each option: - (a) solid is dispersed in gas - (b) gas is dispersed in solid - (c) gas is dispersed in liquid - (d) liquid is dispersed in water Understand what each option means in terms of colloid classification and identify the correct match for an aerosol.

Step 4: Determine Correct Answer

In an aerosol, tiny solid or liquid particles are dispersed in a gas. For this question, we're focusing on aerosols which specifically have solid particles dispersed in gas.

Key Concepts

Aerosols

Aerosols are fascinating types of colloids, often encountered in everyday life. They comprise tiny particles, either solid or liquid, that are dispersed throughout a gas. This unique combination allows aerosols to be highly versatile and common in natural and man-made environments. Examples include:

• Mist, where liquid water droplets are suspended in air.
• Smoke, which consists of solid particles dispersed in air.
• Hairspray, an everyday product that releases liquid particles into a gas.

Aerosols are important in various applications and phenomena. For instance:

• Environmental science focuses on aerosols for air quality and climate effects.
• Medicine uses aerosols for inhalers that deliver medication directly to the lungs.

The key characteristic of aerosols is their composition of a dispersed phase and a dispersing medium, which are distinct yet interdependent parts of the whole structure.

Dispersed Phase

The dispersed phase in a colloid, such as an aerosol, refers to the particles that are distributed throughout another substance. These particles can be either solid or liquid, depending on the type of aerosol. In an aerosol, the dispersed phase is what makes the composition unique:

• For liquid aerosols like mists, the dispersed phase is made up of tiny liquid droplets.
• In solid aerosols such as smoke, the dispersed phase consists of small solid particles.

The size and composition of the dispersed phase significantly affect the behavior and properties of the aerosol. For example,

• Small particle size can enable particles to remain suspended in the gas for extended periods.
• Larger or heavier particles may settle quicker due to gravity.

Understanding the dispersed phase can therefore provide insights into the stability, behavior, and applications of different aerosol types.

Dispersing Medium

The dispersing medium in an aerosol is the continuous phase that holds the dispersed particles. In the context of aerosols, the dispersing medium is always a gas. This gas serves as the environment through which solid or liquid particles are distributed. For instance, in atmospheric aerosols:

• The dispersing medium is typically air, providing the space and support for particles like dust or water droplets.

The properties of the dispersing medium, such as its temperature and humidity, can significantly influence how the dispersed phase behaves within the colloid.

• For example, high humidity might lead to larger water droplets forming in mist, impacting visibility and possibly causing fog.
• In contrast, lower temperatures can affect the diffusion and suspension of particles in the air.

The interaction between the dispersed phase and the dispersing medium is crucial for understanding and manipulating aerosol behaviors in various scientific and industrial contexts.