Given below are two statements:
Statement I: Fuel oxides of nitrogen (NOx) is created when nitrogen and oxygen in the combustion chamber are heated to as high as 1000° C temperature.
Statement II: Thermal NOx is often the dominant source in the total NOx emissions.
In the light of the above statements, choose the most appropriate answer from the options given below:
Both Statement I and Statement II are false
Both statements describe sources of oxides of nitrogen (NOx) formed during combustion, but need to be checked against correct combustion chemistry.
Statement I claims that heating nitrogen and oxygen together in the combustion chamber to about 1000°C produces 'fuel NOx'. This is incorrect on two counts: first, NOx formed from atmospheric nitrogen (N2) and oxygen (O2) reacting at high flame temperatures is called thermal NOx, not fuel NOx — fuel NOx instead originates from nitrogen chemically bound within the fuel itself, which oxidises during combustion largely independent of flame temperature. Second, thermal NOx formation only becomes significant at much higher temperatures, typically above about 1300°C and rising sharply above 1600°C; at around 1000°C the thermal pathway contributes very little. So Statement I is false.
Statement II claims thermal NOx is often the dominant source of total NOx emissions. While thermal NOx can dominate in very high-temperature processes such as gas turbines, in many common combustion sources, particularly coal and other nitrogen-rich fuel combustion, fuel NOx arising from nitrogen already present in the fuel is typically the larger contributor to total NOx emissions. As a general statement about total NOx emissions this is therefore not correct, making Statement II false as well.
Hence both statements are false.
Similar Questions
Give below are two statements:
Statement I : Thermal pollution, usually effluent from cooling systems of power plants or other industries, alters water temperature in a lake or stream.
Statement II : Humans also cause thermal pollution by altering vegetation cover and run-off patterns.
In the light of the above statements, choose the correct answer from the options given below:
Major contributor to carbon monoxide emissions in metropolitan areas of India is/are:
The most important pollutants that cause degradation of water quality in rivers and streams are
(a) Bacteria
(b) Nutrients
(c) Metals
(d) Total dissolved solids
(e) Algae
Choose the most appropriate answer from the options given below:The most dominant source of Benzene emissions in ambient air is
Major sources of oxygen demanding waste in fresh water systems are
(a) Agricultural run-off
(b) Food processing
(c) Ore mining
(d) Sewage effluent
(e) Landfill sites
Choose the correct option from those given below: -
Which of the following pollutant gases is not produced both naturally and as a result of industrial activity?
Which of the following pollutants is the major cause of respiratory diseases?
Assertion (A): In urban areas, smog episodes occur frequently in winters.
Reason (R): In winters, a lot of biomass is burnt by people for heating purposes or to keep themselves warm.
Choose the correct answer from the code given below:
With increase in temperature, the dissolved oxygen content in a water body will:
In the formation of Surface Ozone, which of the following do play an important role?
(a) Oxides of nitrogen
(b) Oxides of sulphur
(c) Sunlight
(d) Carbon monoxide
Choose the correct answer from the code given below:
Important Questions from Pollution
Which of the following isnota common component of photo-chemical smog?
Which of the following is NOT the main objective of Ganga action plan?
Which of the following pollutants causes water pollution ?
Presence of which pathogenic microbe in water is indication of contamination?
Which of the following isnota vehicular pollutant?
