Question

The relation between density of air ($Da$) and water vapour ($Dco$) is:

• A. $Da=Dco$
• B. $Da>Dco$
• C. $Da<Dco$
• D. $Da\le Dco$

Answer 1

The correct option is B $Da>Dco$

Water vapour is relatively light gas compared to diatomic oxygen and diatomic nitrogen (air).

Thus, when water vapour increases the amount of oxygen and nitrogen decreases per unit volume. Thus density decreases because mass is decreasing.

So, $D_{air}>D_{watervapour\left(CO\right)}$

$D_a>D_{CO}$