The rough value of diffusion co-efficient of water vapor into air at 25°C may be about __________ cm²/sec.

ANS:A - 0.25

The rough value of the diffusion coefficient of water vapor into air at 25°C is approximately 0.25 cm²/sec. Diffusion coefficients can vary depending on factors such as temperature, pressure, and the specific gases involved. However, for rough estimations, a value around 0.25 cm²/sec is commonly used for the diffusion coefficient of water vapor into air at 25°C under typical atmospheric conditions.