Which gas combines with haemoglobin to form carboxyhaemoglobin, making it unable to carry oxygen?
- A.Carbon dioxide
- B.Carbon monoxide
- C.Sulphur dioxide
- D.Nitrous oxide
Correct answer
Explanation
The correct answer is B, carbon monoxide. Carbon monoxide binds to haemoglobin far more strongly than oxygen does and forms carboxyhaemoglobin, so the blood cannot pick up oxygen even though breathing goes on; the gas is colourless and odourless, which makes it the more dangerous, and it is produced by the incomplete burning of fuel in closed rooms and in engines. Option A, carbon dioxide, is wrong because it is carried in the blood as bicarbonate and is the normal waste gas of respiration, dangerous only in very high concentration. Option C, sulphur dioxide, is wrong because it irritates the eyes and the respiratory tract and causes acid rain rather than this blood effect. Option D, nitrous oxide, is wrong because it is the mild anaesthetic known as laughing gas.
Read the full article: Important Gases and Their Uses: Notes and PYQs
Practice Questions
View allWhich gas is typically produced when a metal reacts with an acid?
- A.Carbon dioxide
- B.Oxygen
- C.Hydrogen
- D.Nitrogen
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A metal more reactive than hydrogen displaces it from a dilute acid, so zinc with dilute sulphuric acid gives zinc sulphate and hydrogen gas, and this is the standard laboratory preparation of the gas; the test is that it burns with a pop.
Read the full explanation →Which of the following is a radioisotope of hydrogen?
- A.Xenon
- B.Technetium
- C.Thorium
- D.Tritium
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Hydrogen has three isotopes: protium with one proton and no neutron, deuterium with one neutron, which gives heavy water, and tritium with two neutrons, which is radioactive and is used in fusion research and in luminous dials.
Read the full explanation →Ozone depletion is greatest near
- A.tropics
- B.equator
- C.poles
- D.oceans
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Chlorine released from chlorofluorocarbons destroys ozone fastest where polar stratospheric clouds form in the extreme cold of winter, because those ice clouds hold the chlorine compounds that sunlight then breaks up; the thinning is therefore deepest over Antarctica, where it is called the ozone hole, and is seen over the…
Read the full explanation →Which gas is commonly known as laughing gas?
- A.Nitric oxide
- B.Nitrogen dioxide
- C.Nitrous oxide
- D.Ammonia
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It is called laughing gas because it produces a feeling of elation when inhaled in small quantities, and it is used as a mild anaesthetic in dentistry and minor surgery and as the propellant in whipped cream; it is also a greenhouse gas.
Read the full explanation →Which gas is filled in electric bulbs so that the filament lasts longer?
- A.Oxygen
- B.Argon
- C.Chlorine
- D.Carbon dioxide
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Argon is chemically inert, so the hot tungsten filament does not react with it, and its presence also slows the evaporation of tungsten, which is why bulbs are filled with argon, sometimes mixed with nitrogen, instead of being left as a vacuum.
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