446: Acid rain is caused by the pollution of environment by
(a) carbon dioxide and nitrogen
(b) carbon monoxide and carbon dioxide
(c) ozone and carbon dioxide
(d) nitrous oxide and sulphur dioxide
Explanation:
Acid rain is caused by emission by sulphur dioxide and nitrous oxide which react with water in the atmosphere to form acid.
447: Which of the following statements are correct about the deposits of methane hydrate?
1. Global warming might trigger the release of methane gas from these deposits.
2. Large deposits of methane hydrate are found in Arctic Tundra and under the seafloor.
3. Methane in atmosphere oxidizes to carbon dioxide after a decade or two.
Select the correct answer using the code given below.
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
Explanation:
Statement 1 is correct - Methane escaping from disturbed undersea hydrates may be an ecological threat. Even if a small portion of these methane hydrate deposits decompose through natural processes, large quantities of methane will be released to exacerbate global warming.
Statement 2 is correct - Methane hydrates tend to form along the lower margins of continental slopes, where the seabed drops from the relatively shallow shelf, usually to about 150 metres below the sea surface. The susceptibility of gas hydrates to warming climate depends on the duration of the warming event, their depth beneath the seafloor or tundra surface, and the amount of warming required to heat sediments to the point of dissociating gas hydrates.
Statement 3 is correct - The problem with methane is that it does not vanish without a trace, even though it remains in the atmosphere relatively briefly - 10 years on an average. In the presence of free oxygen, a methane molecules single atom of carbon disengages from its four hydrogen atoms to become carbon dioxide.
Source: https://www.downtoearth.org.in/news/burning-ice-17856
448: Which one of the following is in the correct sequential order in which these appeared under simulated primitive earth condition ?
(a) Methane, Hydrogen cyanide, nitriles, aminoacids
(b) Hydrogen cyanide, methane, nitriles, aminoacids
(c) Aminoacids, nitriles. Hydrogen cyanide, methane
(d) Nitriles, aminoacids, methane, Hydrogen cyanide
449: Which one of the following types of coal contains a higher percentage of carbon than the rest ?
(a) Bituminous coal
(b) Lignite
(c) Peat
(d) Anthracite
Explanation:
Anthracite contains 80-90% carbon. It is the type of coal which contains higher percentage of carbon.
Bituminous coal - 70-90% carbon
Lignite/Brown coal - 45-75% carbon
450: With reference to food chains. In ecosystems, consider the following statements:
1. A food chain illustrates the order in which a chain of organisms feed upon each other.
2. Food chains are found within the populations of a species.
3. A food chain illustrates the numbers of each organism which are eaten by others.
Which of the statements given above is/are correct?
(a) 1 only
(b) 1 and 2 only
(c) 1, 2 and 3
(d) None
Explanation:
I think this question needs no explanation - very easy