Normal diffusion of CO2 at rest-

Ans. (d) 300-400 ml/min/mm Hg(Ref: Ganong, 25th ed/p.640)Normal value of DLCO is 25 mL/min/mm HgDiffusion coefficient of O2 is about 1.23 times that of COSo, Diffusing capacity for oxygen is 25*1.23=30mL/min/mmHgDiffusion capacity of CO2 is 400 ml/min/mm Hg