The incomplete burning of petrol and diesel produces :
Correct Answer:
(D)
carbon monoxide
In the complete combustion (burning) of hydrocarbon fuels (i.e. petrol and diesel), hydrocarbons react with oxygen and water and carbon dioxide are produced. Incomplete combustion occurs when the supply of air or oxygen is poor. In the incomplete combustion of hydrocarbon fuels water is still produced, but carbon monoxide (a poisonous gas) and carbon (as soot) are produced instead of carbon dioxide.
Ques:
62
The relative contributions of carbon dioxide (CO2), nitrous oxide (N2O), chlorofluorocarbons (CFCs) and methane (CH4) towards global warming are :
Correct Answer:
(D)
CO2 > CH4 > N2O > CFCs
The relative contribution of main greenhouse gases towards global warming are as follows :
(i) Water vapour - about 60%
(ii) Carbon dioxide (CO2) - about 26%
(iii) Methane (CH4) - about 4-9%
(iv) Ozone (O3) - about 3-7%
(v) Nitrous oxide (N2O) - about 1.5%
(vi) Chlorofluorocarbons (CFCs) and others - 0.1-0.4%
Thus, it is clear that option (d) is correct.
Ques:
63
Consider the following statements:
Assertion (A) : A dry cell cannot be charged.
Reason (R) : Dry cell has a reversible reaction.
Code :
(A) and (R) are true and (R) is the correct explanation of
(A).
Correct Answer:
(C)
is true, but (R) is false.
The matters of a dry cell are there in dry form. A zinc pot is there having full of manganese dioxide, salammoniac and carbon. This cell cannot be charged because the chemical reaction in it cannot be reversed.
Ques:
64
Carbon Nanotubes (CNTs) were prepared by –
Correct Answer:
(B)
Iijima
Sumio Iijima is a Japanese physicist, often cited as the inventor of carbon nanotubes.
Ques:
65
In the context of which one of the following are the terms ‘pyrolysis and plasma gasification’ mentioned?
Correct Answer:
(D)
Waste-to-energy technologies
Like incineration, plasma pyrolysis and gasification technologies are thermal processes that use high temperatures to break down waste. Plasma gasification system facilitates safe disposal of all type of organic wastes. The inorganic materials like glass, metals can also be minimized to slag. In plasma pyrolysis the most likely compounds which are produced include carbonaceous matter, methane, carbon monoxide, hydrogen, carbon dioxide and water molecules. The product gases recovered has calorific and commercial values. These gases can be used as a heat source or as fuel. NITI Ayog in his three-year Action Agenda (2017-2020), has also assessed the benefit-cost ratio of thermal pyrolysis and plasma gasification as waste-to-energy technologies.
Ques:
66
Which one of the following pairs is correctly matched?
Correct Answer:
(D)
Ozone depletion - Skin cancer
The correctly matched Pairs are :
Sulphur dioxide - Acid rain
Fluoride pollution - Teeth
Methyl isocyanate - Bhopal gas tragedy
Ozone depletion - Skin cancer
Thus, it is clear that option (d) is correctly matched.
Ques:
67
Discharge of nitrogen causes –
Correct Answer:
(C)
The amount of nitrogen in lithosphere and in atmosphere unchanged
The nitrogen cycle is a process by which nitrogen is converted into its various chemical forms. This transformation can be carried out through both biological and physical processes. The nitrogen cycle includes fixation, ammonification, nitrification and denitrification. Denitrifying bacteria converts nitrate and nitrite ions into nitrogen. From discharge of this nitrogen, its amount in the lithosphere and in atmosphere remains unchanged.
Ques:
68
Which one of the following is the permanent gas in the atmosphere?
Correct Answer:
(C)
Nitrogen
Permanent Gases are those gases which are believed to be incapable of liquefaction and remains gaseous under normal conditions. These gases include hydrogen, nitrogen, carbon monoxide etc. Nitrogen is a permanent gas in the atmosphere. It accounts for about 78% of the atmosphere.
Ques:
69
The gas used to inflate the tyres of an aircraft is –
Correct Answer:
(B)
Nitrogen
Nitrogen gas is used in the tyres of an aero plane. This is because the nitrogen gas does not support combustion and can assist in preventing wheel fire when the aircraft lands (braking and high speed can produce dangerously high temperatures) unlike in oxygen. There are other benefits but effectively it is being the lowest cost gas that does not support combustion.
Ques:
70
Tear gas is :
Correct Answer:
(B)
Chlorine
Tear gas is a chemical weapon that causes severe eye and respiratory pain, skin burning, vomiting and even blindness. In the eye, it stimulates the nerves of the lacrimal gland to produce tears. It is mostly used by the police force in controlling riots. Alpha chloroacetophenone, 2-chlorobenzalmalononitrile and acrolein are generally used as tear gas. Chlorine (Cl2) is also used in preparation of tear gas.