Question

Equimolar samples of CH3OH(l) and C2H5OH(l) are placed in separate, previously evacuated, rigid 2.0 L vessels. Each vessel is attached to a pressure gauge, and the temperatures are kept at 300 K. In both vessels, liquid is observed to remain present at the bottom of the container at all times. The change in pressure inside the vessel containing CH3OH(l) is shown below.Compared to the equilibrium vapor pressure of CH3OH(l) at 300 K, the equilibrium vapor pressure of C2H5OH(l) at 300 K is

Answer 1

Answer:

Complete Question:  

Equimolar samples of CH3OH(l) and C2H5OH(l) are placed in separate, previously evacuated, rigid 2.0 L vessels. Each vessel is attached to a pressure gauge, and the temperatures are kept at 300 K. In both vessels, liquid is observed to remain present at the bottom of the container at all times. The change in pressure inside the vessel containing CH3OH(l) is shown below.

Compared to the equilibrium vapor pressure of CH3OH(l) at 300 K, the equilibrium vapor pressure of C2H5OH(l) at 300 K is

ANSWER : lower, because London dispersion forces among C2H5OH molecules are greater than those among CH3OH molecules

Explanation:

In Order to get a good understanding the answer above let first define some terms

The London dispersion force is the weakest inter-molecular force. The London dispersion force is a temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles.  

The vapor pressure of a liquid is the equilibrium pressure of a vapor above its liquid (or solid); that is, the pressure of the vapor resulting from evaporation of a liquid (or solid) above a sample of the liquid (or solid) in a closed container

The pressure will be Lower, because London dispersion forces among C2H5OH molecules are greater than those among CH3OH molecules ,What this means is that the stronger the inter-molecular forces, the stronger the interactions that hold the substance together, hence the lower the vapor pressure of the liquid at a given temperature, and the harder it is to vaporize the  substance.

Note: London dispersion force among C2H5OH molecules is higher than that among CH3OH molecules because the number of electrons in C2H5OH is greater than that in CH3OH.