Problem 62 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following colloidal solution is used in photography? (a) colloidal silver bromide (b) colloidal gold (c) colloidal silver (d) colloidal sulphur

Step-by-Step Solution

Answer

Colloidal silver bromide is used in photography.

Step 1: Identify Key Concepts

To solve this problem, you need to understand what a colloidal solution is and its application in photography. Photography involves the use of substances that are sensitive to light.

Step 2: Recognize Photographic Materials

In the context of photography, silver bromide is a compound commonly used due to its photosensitive properties, meaning it reacts to light, an essential characteristic for photographic development.

Step 3: Assess Each Option

Examine each colloidal option given: (a) colloidal silver bromide is used in photography due to its photosensitivity; (b) colloidal gold doesn't have a direct role in photography; (c) colloidal silver is not typically used in traditional photography; (d) colloidal sulphur is also not used in photography.

Step 4: Select the Correct Answer

Based on the above assessments, colloidal silver bromide (a) is the correct answer as it is widely used in the photographic process due to its sensitivity to light.

Key Concepts

Silver Bromide

Silver bromide is a chemical compound composed of silver and bromine. It plays a crucial role in photography due to its unique properties. This compound forms a key component in the traditional photographic industry.
- **Composition and Structure:** Silver bromide is represented chemically as AgBr. It is a white or pale yellow crystalline solid.
- **Colloidal State:** In photography, silver bromide is used in a colloidal state, which is a stable dispersion of the particles of one substance within another. This allows for the great photosensitive property of silver bromide to be utilized effectively.
- **Applications:** In photography, it is the primary photosensitive agent in silver halide emulsions, found in traditional film and photographic paper.
These emulsions are responsible for capturing images when exposed to light.

Photography

Photography is the art and science of capturing images using light. It relies heavily on chemical compounds that can react to light.
- **Development Process:** Traditional photography uses films coated with light-sensitive materials such as silver bromide. When light passes through the camera lens, it strikes the silver bromide particles in the film, causing a reaction that slowly builds an image.
- **Printing Process:** After the film is exposed, the development process involves chemical baths that develop an image from the latent silver bromide reaction.
The developed negatives or photographs hold onto these images permanently.
- **Evolution Over Time:** While digital photography is now widely prevalent, understanding traditional processes like those using silver bromide is essential to grasp the roots of photographic technology.
The silver bromide process exemplifies how light interaction with chemicals creates lasting images, a foundation for modern photography.

Photosensitivity

Photosensitivity refers to the sensitivity of a material to light, crucial for processes like photography.
- **Role in Photography:** Materials like silver bromide change chemically when exposed to light, a defining trait of photosensitive materials. This reaction initiates the formation of an image.
- **Mechanism:** When light strikes silver bromide, it leads to the breakdown of the compound and releases elemental silver, which forms a latent image. This latent image is not visible until it undergoes further chemical processing.
- **Importance in Photographic Technology:** Without photosensitivity, capturing light and translating it into images as seen in photographic film would not be possible.
By utilizing photosensitive compounds like silver bromide, traditional photography could accurately record and preserve visuals through chemical interactions, a concept still integral to modern technologies.