Chemistry - Study Mode

[#286] The chemical used in developing photographic films is
Correct Answer

(A) Silver bromide

Explanation

Solution: In photography, silver bromide is used on photographic film, because it is unusually sensitive to light exposure.

[#287] Which one of the following is used as an anti-freeze for the automobile engines ?
Correct Answer

(D) Ethylene glycol

Explanation

Solution: Ethylene glycol is a chemical commonly used in many commercial and industrial applications including antifreeze and coolant. Ethylene glycol helps keep your car's engine from freezing in the winter and acts as a coolant to reduce overheating in the summer.

[#288] Milk is
Correct Answer

(A) Emulsion

Explanation

Solution: Milk is emulsion.

[#289] Milk is a natural
Correct Answer

(B) Emulsion

Explanation

Solution: An emulsion is a mixture of two or more liquids that are normally immiscible (nonmixable or unblendable). Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both the dispersed and the continuous phase are liquids. In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, milk, mayonnaise, and some cutting fluids for metal working. The photo-sensitive side of photographic film is also an example of a colloid. The word “emulsion” comes from the Latin word for “to milk”, as milk is (among other things) an emulsion of milk fat and water.

[#290] Emulsifier is an agent which
Correct Answer

(C) Stabilizes an emulsion

Explanation

Solution: An emulsifier is a substance that stabilizes an emulsion by increasing its kinetic stability. One class of emulsifiers is known as “surface active substances”, or surfactants. Many different emulsifiers are used in pharmacy to prepare emulsions such as creams and lotions. Common examples include emulsifying wax, cetearyl alcohol, polysorbate 20, and ceteareth 20. Sometimes the inner phase itself can act as an emulsifier, and the result is a nanoemulsion, where the inner state disperses into “nano-size” droplets within the outer phase. A well-known example of this phenomenon, the “Ouzo effect”, happens when water is poured into a strong alcoholic anise-based beverage, such as ouzo, pastis, arak, or raki. The anisolic compounds, which are soluble in ethanol, then form nano-size droplets and emulsify within the water. The resulting colour of the drink is opaque and milky white.