What will be the `pO_(2) and pCO_(2)` in the atmospheric air compared to those in the alveolar air?
(i) `pO_(2)` lesser, `pCO_(2)` higher
(ii) `pO_(2)` higher, `pCO_(2)` lesser
(iii) `pO_(2)` higher, `pCO_(2)` higher
(iv) `pO_(2)` lesser, `pCO_(2)` lesser

Explanation

(ii) `pO_(2)` higher, `pCO_(2)` lesser
The partial pressure of oxygen in atmospheric air is higher than that of oxygen in alveolar air. In atmospheric air, `pO_(2)` is about 159 mm Hg. In alveolar air, it is about 104 mm Hg. The partial pressure of carbon dioxide in atmospheric air is lesser than that of carbon dioxide in alveolar air. In atmospheric air, `pCO_(2)` is about 0.3 mmHg. In alveolar air, it is about 40 mm Hg.