Question

In an experiment to check the amount of carbon dioxide, atmospheric air and exhaled air is passed through lime water. Which of the following turns lime water milky?
A) Exhaled air
B) Atmospheric air
C) Both exhaled air and atmospheric air
D) None of the above

Answer 1

Hint: Gaseous exchange occurs in order to ensure that the process of respiration, digestion and also the removal of waste substances takes place. The perfect time to determine if the carbon dioxide is, to pass it through the solution of lime water. When lime water is turned milky, the presence of carbon dioxide is detected.

Complete answer:
During the process of gaseous exchange two main processes occurs usually, which are;
i) Inhalation – Inhaled air has more oxygen which is used to create energy and less carbon dioxide.
ii) Exhalation – Exhaled air contains more carbon dioxide and is generated as a waste to be removed and less oxygen is being produced.

According to the experiment when the carbon dioxide passes through lime water it turns the water cloudy. Both atmospheric air in which it is naturally present and also the air that is come out from lungs contains some amount of carbon dioxide as the cells break down molecules like fat, carbohydrates, and various others to capture energy from them.

During the process of gaseous exchange, exhalation and also the process of inhalation prevails as a result of exchange and diffusion through the alveoli. The carbon dioxide from the blood is exchanged and is exhaled by the process of exhalation and the oxygen that is present in the alveoli diffuses to the blood.

Therefore, the correct option is ‘C’ which says that 'Both exhaled air and atmospheric air' turns lime water milky.

Note: The concentration of carbon dioxide is considered to be more in exhaled air compared to the inhaled air because it contains more waste from the body and expels it outside of the body. Carbon dioxide is eliminated so the blood will get purified and more of the oxygenated blood will be remaining inside the body.