December 14, 2015

Junior Inter Chemistry - 2 Marks Imp Questions - Organic and Environmental Chemistry

Q: Define "COD". How is it determined?
A: The amount of oxygen required to oxidise organic material present
in polluted water. It is determined with acidified (50% H2SO4)
K2Cr2O7.

Q: Define "Sink" and "Receptor".
A: Sink: The medium which is not only effected by the pollutant but
also remains there. Trees are sinks of CO2.
Receptor: The medium which is badly effected by the pollutant. Eyes
are receptors during traffic jam.

Q: What is "Threshold Limit Value" (TLV)?
A: The permissible level of a toxic pollutant in atmosphere where a
healthy person works in that atmosphere for 8 hours per day without
any adverse effect.

Q: What is "green house effect"?
A: The phenomenon of gradual rise of temperature of earth due to
absorption of infrared radiation of sun rays by the gases like CO2,
CH4, CFCs and O3.

Q: Which oxides cause acid rains? What is its pH value?
A: Acid rains are caused by the oxides NO2 and SO2 (due to formation
of H2SO4, HNO3) when they reacts with O2 & H2O. pH of acid rain water
is below 5.6.

Q: Name two adverse effects caused by acid rains.
A: Decrease of fertility of soil as acid rains dissolve nutrients and
washes away.
Damage of historical monuments like Taj Mahal.

Q: What is "ozone hole"? Where was it first observed?
A: The depletion of ozone layer present in stratosphere is caused by
CFCs. It was first observed over the south pole.

Q: What are the harmful effects caused by ozone layer depletion?
A: Causes skin cancer & cataract.
Damage to fish productivity.
Paints & fibres fade faster.
Decrease of moisture in soil.

Q: What is 'Eutrophication'?
A: Drying of lake due to overgrowth & decay of algae and other plants
& killing of fish (due to lack of oxygen) due to over nutrition of
lake water.

Q: What is "Green Chemistry"?
A: New branch of Chemistry which helps in reduction in the production
& use of harmful pollutants by using existing knowledge of Chemistry
and other sciences.

Q: Explain the principle of Chromatography.
A: The technique in which the mixture of substances is applied on
stationary phase (solid or liquid) and a mobile phase (gas or solvent)
is allowed to move slowly over the stationary phase. The components
are separated from one another in pure form.

Q: What is "Carcinogenicity"? Name two compounds cause it.
A: Cancer producing property by fused benzene rings (3 or more), which
are formed due to incomplete combustion of tobacco, coal and
petroleum.
Eg: 1, 2, - Benzpyrene, 1, 2 - Benzanthracene

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