Air Around Us-III

Exhaled air contains all the components of inhaled air, but in different proportions: nitrogen remains the largest component, oxygen decreases (some used in respiration), carbon dioxide increases (produced by respiration), and water vapor is added. Therefore all four - N2, CO2, O2, and water vapour - are present.

Argon is used to fill light bulbs to inhibit the evaporation of the tungsten filaments and increase bulb life.

Nitrogen dioxide is not a greenhouse gas.

Thermal power stations burn fossil fuels releasing CO2 and particulates. Nuclear plants produce radioactive waste (though minimal air pollution during normal operation). Cement factories release significant dust and CO2. Hydroelectric plants, however, use flowing water to generate electricity without combustion or emissions - they don't cause air pollution.

Air is invisible and has no smell or taste. However, we can feel air through wind, air pressure against skin, or the sensation of breathing. The other options are incorrect because air cannot be seen, smelled, or tasted - it's the impurities or movement in air that we perceive.

During welding air pollutants are released and ozone is the most abundant of all of theses pollutants. 

Air is a mixture of various gases. The main gases present in air are nitrogen (78.1% by volume) and oxygen (20.9% by volume). These two gases together form 99% of the air. Besides these two, air contains small amounts of carbon dioxide (0.03 to 0.04%), water vapour (variable), noble gases (0.94%), and dust particles.

Oxygen present in air reacts wiyh nitric oxide results of form reddish brown gas.

Carbondioxide turns lime water milky.

When a cold glass sits in warm air, water vapor in the air contacts the cold surface and condenses into liquid droplets on the outside. This is condensation - the same process that causes dew on grass. The water doesn't freeze, change color, or evaporate; droplets form on the exterior due to temperature difference.

The main gas present in the air is nitrogen (78.1% by volume) and it helps in diluting the effect of oxygen. The noble gases present in the air are helium, neon, argon, krypton and xenon. Since the percentage of these gases is very small, so, these gases are also called "rare gases".

Respiration is the process where living organisms use oxygen to break down food, releasing carbon dioxide, water vapor, and energy. Option C incorrectly reverses this - claiming respiration uses CO2 and produces O2, which describes photosynthesis, not respiration. The statement 'uses carbon dioxide and produce oxygen' is the opposite of actual respiration.

Air is a mixture, not a compound. Mixtures cannot be represented by single chemical formulas because they contain multiple substances that don't combine chemically. The components of air (nitrogen, oxygen, argon, CO2, water vapor) retain their individual properties and proportions can vary, which is why there's no single formula like there is for compounds.

In a mixture, each component keeps its original chemical properties. Oxygen alone supports burning, and oxygen in air also supports burning because it remains oxygen even when mixed with nitrogen and other gases. This demonstrates that mixture components behave as they would individually. Option A shows composition variability, not property retention.

Oxygen is abundant in the plains as compared to high altitudes.

Inhaled air has about 21% oxygen and 0.04% carbon dioxide. During respiration, oxygen is absorbed and carbon dioxide is released, so exhaled air contains less oxygen (about 16%) and more carbon dioxide (about 4-5%). Exhaled air is warmer (body temperature) and more humid due to moisture from respiratory surfaces, not cooler or drier.

Nitrogen is the main component of air and oxuygen is used in the process of respiration and green plants used carbon dioxide for food manufacturing.

Nitrogen > oxygen > argon > carbon dioxide > other gases is the correct answer.

Air is present in the troposphere layer of atmosphere.