Practice MCQ Questions and answers on Chemistry-GK

Peroxyacetyl nitrate is a secondary pollutant present in photochemical smog. It is thermally unstable and decomposes into peroxyethanoyl radicals and nitrogen dioxide gas. It is a lachrymatory substance.

Natural pollution comes from natural sources like release of methane by cattle and paddy fields, carbon dioxide from plants and animals, dust storms, nitrogen oxides, ozone, volcanic eruptions, emission of natural gas, sol erosion, ultraviolet rays,etc. Mercury is not a cause of natural pollution.

Nature gas is 95 percent Methane (CH₄) plus four other hydrocarbons:
Ethane (C₂H₆) - 2.5 %, Propane (C₃H₈) - 0.2 %, Butane (C₄H₁₀) - 0.06%, Pentanes Plus (C₅H₁₂ + C₁₀H₂₂) -0.02%. It also contains small amounts of: Nitrogen (N₂) - 1.6%, Carbon Dixoide (CO₂) - 0.7%, Hydrogen Sulphide (H₂S) - trace, Water (H₂O) - trace.

Particulate matter consists of millions of tiny particles of diverse chemical composition. Particulate matter from tobacco smoke includes many particles in the size range that reflects light, which explains why tobacco smoke is easily seen by the eye. In contrast to smoke particles, gases emitted by the cigarette such as benzene and carbon monoxide (CO) are invisible to the eye. Particles smaller than 2.5 micrometers (PM2.5) are major components of cigarette smoke and can enter deep into the lung where they can cause serious health problems. The pollutants generated by the cigarette arise from the chemical process of burning organic matter, or combustion of tobacco and paper. Combustion processes, such as wood burning or waste incineration, emit thousands of pollutants, some of which are in the gas phase and some of which are in the form of small particles called particulate matter.

Aluminium is not a pollutant.

Carbon monoxide is the main pollutant present in automobile exhaust.

Sullage is all wastewater generated in households or office buildings from streams without fecal contamination, i.e. all streams except for the wastewater from toilets. Sources of sullage include, e.g. sinks, showers, baths, clothes washing machines or dish washers.

Most poisonous pollutant in water is arsenic.

Recent research has shown that India’s groundwater faces the problem of presence of uranium, arsenic, and heavy metals in ground water used for drinking. Sorbitol (used as artificial sweetener) and Formaldehyde (used in coating, etc) are not famous as water pollutants.

Smog is air pollution that reduces visibility. The term "smog" was first used in the early 1900s to describe a mix of smoke and fog. The smoke usually came from burning coal. Smog was common in industrial areas, and remains a familiar sight in cities today. Today, most of the smog we see is photochemical smog.