A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Cloud is a colloidal dispersion of Water drops in a dispersion medium of air.

Correct Option: D

A colloid is a substance microscopically dispersed evenly throughout another substance. A colloidal system consists of two separate phases: a dispersed phase (or internal phase) and a continuous phase (or dispersion medium) in which the colloid is dispersed. A colloidal system may be solid, liquid, or gas. Cloud is a colloidal dispersion of Water drops in a dispersion medium of air.

Aspirin (USAN), also known as acetylsalicylic acid., is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. Aspirin was first isolated by Felix Hoffmann, a chemist with the German company Bayer in 1897. Salicylic acid, the main metabolite of aspirin, is an integral part of human and animal metabolism. While in humans much of it is attributable to diet, a substantial part is synthesized endogenously.

Correct Option: C

Aspirin (USAN), also known as acetylsalicylic acid., is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. Aspirin was first isolated by Felix Hoffmann, a chemist with the German company Bayer in 1897. Salicylic acid, the main metabolite of aspirin, is an integral part of human and animal metabolism. While in humans much of it is attributable to diet, a substantial part is synthesized endogenously.

The excretory system functions in ridding the body of nitrogenous (nitrogen-containing, discussed below) and other wastes. Nitrogenous wastes of animals are excreted in form of ammonia, urea, or uric acid. They are excreted in the urine. Because ammonia is so water-soluble, aquatic animals often can get rid of it just by diffusion into the surrounding water. That’s one reason why the water in your aquarium gets “bad” and needs to be changed, and why not changing the water could kill the fish. However, ammonia doesn’t readily go from body fluids into air, so terrestrial animals need other ways of getting rid of nitrogenous wastes.

Correct Option: C

The excretory system functions in ridding the body of nitrogenous (nitrogen-containing, discussed below) and other wastes. Nitrogenous wastes of animals are excreted in form of ammonia, urea, or uric acid. They are excreted in the urine. Because ammonia is so water-soluble, aquatic animals often can get rid of it just by diffusion into the surrounding water. That’s one reason why the water in your aquarium gets “bad” and needs to be changed, and why not changing the water could kill the fish. However, ammonia doesn’t readily go from body fluids into air, so terrestrial animals need other ways of getting rid of nitrogenous wastes.

Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. CFCs were invented by Thomas Midgley, Jr. in the 1920s. They were used in air conditioning and cooling units, as aerosol spray propellants prior to the 1970s, and in the cleaning processes of delicate electronic equipment. They also occur as by-products of some chemical processes. No significant natural sources have ever been identified for these compounds their presence in the atmosphere is due almost entirely to human manufacture.

Correct Option: C

Chlorofluorocarbons (CFCs) and other halogenated ozone depleting substances (ODS) are mainly responsible for man-made chemical ozone depletion. CFCs were invented by Thomas Midgley, Jr. in the 1920s. They were used in air conditioning and cooling units, as aerosol spray propellants prior to the 1970s, and in the cleaning processes of delicate electronic equipment. They also occur as by-products of some chemical processes. No significant natural sources have ever been identified for these compounds their presence in the atmosphere is due almost entirely to human manufacture.

Ethylene is a rather stable molecule that polymerizes only upon contact with catalysts. The conversion is highly exothermic, that is the process releases a lot of heat. Coordination polymerization is the most pervasive technology, which means that metal chlorides or metal oxides are used. The most common catalysts consist of titanium (III) chloride, the so-called Ziegler-Natta catalysts. Another common catalyst is the Phillips catalyst, prepared by depositing chromium (VI) oxide on silica. Ethylene can be produced through radical polymerization, but this route is only limited utility and typically requires high pressure apparatus.

Correct Option: D

Ethylene is a rather stable molecule that polymerizes only upon contact with catalysts. The conversion is highly exothermic, that is the process releases a lot of heat. Coordination polymerization is the most pervasive technology, which means that metal chlorides or metal oxides are used. The most common catalysts consist of titanium (III) chloride, the so-called Ziegler-Natta catalysts. Another common catalyst is the Phillips catalyst, prepared by depositing chromium (VI) oxide on silica. Ethylene can be produced through radical polymerization, but this route is only limited utility and typically requires high pressure apparatus.