Question

Which of the following substances is used in black and white photography ?
1. Sodium Chloride
2. Calcium Hydroxide
3. Calcium Nitrate
4. Silver Bromide

Answer 1

Correct Answer - Option 4 : Silver Bromide

The correct answer is Silver bromide.

• Silver Bromide is used in black and white photography.
• A photographic film is coated with silver bromide. when light falls on the surface, the exposed part of the film is darkened from which photograph is developed. That’s why it is used in photography.
• When we take a picture, the camera lens projects a small but accurate image on the surface of this light-sensitive layer, and the silver bromide is decomposed more or less, depending on the intensity of the light received in various points of the image.
• Silver bromide (AgBr), a soft, pale-yellow, water-insoluble salt well known (along with other silver halides) for its unusual sensitivity to light.

• Calcium nitrate:
  • ​It is mainly used as a nitrogen fertilizer in agriculture and is produced in granulated form.
  • It is also used in wastewater pre-conditioning for odor emission prevention, and inset accelerating concrete admixtures.
• Sodium chloride:
  • NaCl, also known as salt, is an essential compound It is used to flavor and preserves foods.
  • As a preservative, salt helps to prevent spoilage and helps to keep foods like ready-to-eat meats and cheeses safe to eat.
  • Salt is also used in fermenting processes for foods like sauerkraut, pickles, and kefir.
• Calcium Hydroxide:
  • It is used in industrial settings, such as sewage treatment, paper production, construction, and food processing.
  • It also has medical and dental uses.
  • For example, root canal fillings often contain calcium hydroxide.