Explanation:

To understand the solution to this problem, we need to consider the concept of partial pressures and the ideal gas law.

Partial pressures:
The partial pressure of a gas is the pressure that gas would exert if it occupied the same volume on its own. In a mixture of gases, each gas exerts a partial pressure proportional to its mole fraction.

Ideal gas law:
PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature.

Now let's consider the given problem.

We need to mix nitrogen and ethene in a certain ratio so that the partial pressure exerted by each gas is the same. Let's assume that the total pressure of the mixture is P and the mole fraction of nitrogen is x.

Then, the mole fraction of ethene will be (1-x).

According to the ideal gas law, the partial pressure of nitrogen (PN) and ethene (PE) can be calculated as follows:

PN = xP

PE = (1-x)P

Since we want PN = PE, we can equate the two expressions above and solve for x:

xP = (1-x)P

x = (1-x)

2x = 1

x = 1/2

This means that the mole fraction of nitrogen should be 1/2 and the mole fraction of ethene should be 1/2.

Now, let's assume that we have a total mass of M grams of the mixture. Then, the mass of nitrogen (Mn) and ethene (Me) can be calculated as follows:

Mn = xM

Me = (1-x)M

Substituting x = 1/2, we get:

Mn = Me = M/2

Therefore, the mass of nitrogen and ethene that should be mixed so that the partial pressure exerted by each gas is the same is in the ratio 1:1 or option D).