Breathing And Exchange Of Gases

Pulmonary ventilation, often called the minute ventilation, equals tidal volume multiplied by the respiratory rate. Following the respiratory volume concepts in NCERT Class 11, Chapter 17 (Breathing and Exchange of Gases), tidal volume is the air inspired or expired during a normal quiet breath, here 500 mL. Multiplying 500 mL by 12 breaths per minute gives 500 x 12 = 6000 mL per minute, equal to roughly 6 litres per minute, which matches the textbook value for resting healthy adults. The option 512 mL wrongly adds the two numbers instead of multiplying, confusing the arithmetic operation required. The value 4200 mL is close to a typical vital capacity figure and does not represent a per-minute ventilation rate, so it mixes up unrelated lung parameters. The figure 1500 mL approximates expiratory reserve volume territory and again is not obtained by the correct multiplication. Therefore 6000 mL is correct. A range sanity check supports this: resting minute ventilation in humans is conventionally cited as about 6 to 8 litres per minute, and 6000 mL falls squarely at the lower end of that expected physiological window.