# The partial pressure of ethane over a saturated solution containing 0.0656g of ethane is 1 bar. If the solution contains 0.0500g of ethane, then what should be the partial pressure of the gas?

By Ritesh|Updated : November 14th, 2022

(a) 0.762 bar

(b) 0.755 bar

(c) 0.764 bar

(d) 0.772 bar

0.762 bar is the partial pressure of the gas. Henry's law states that a gas's solubility in a liquid is precisely proportionate to its pressure.

The following is the solubility:

X = Kh x P, where X = mole fraction, P = partial pressure, Kh = henry’s constant

The gas mass is inversely proportional to the mole fraction. We can assume that the partial pressure of a gas is directly proportional to its mass for gases with extremely high solubilities.

Here, P ∝ m

Therefore:

P2/P1 = m2/m1

On rearranging we get:

P2 = P1 x m2/m1

Substituting the value we get:

= 1 x 0.05/0.0656

= 0.762 bar

Hence, 0.762 bar is the partial pressure of the gas.

### Henry’s Law

Henry's law, a gas law, states that, when the temperature is held constant, the amount of gas that is dissolved in a liquid is directly proportional to the partial pressure of that gas above the liquid. Henry's law constant (sometimes abbreviated as "kH") is the proportionality constant for this relationship. Henry's law's mathematical formula is provided by:

P ∝ C (or) P = kH.C

Where,

• ‘C’ denotes the concentration of the dissolved gas.
• ‘P’ denotes the partial pressure of the gas in the atmosphere above the liquid.
• ‘kH’ is Henry’s law constant of the gas.

Summary:

## The partial pressure of ethane over a saturated solution containing 0.0656g of ethane is 1 bar. If the solution contains 0.0500g of ethane, then what should be the partial pressure of the gas?

The partial pressure of ethane over a saturated solution containing 0.0656g of ethane is 1 bar. If the solution contains 0.0500g of ethane, then 0.762 bar is the partial pressure of the gas.