Water (h2o) is a liquid at room temperature. ammonia (nh3) is a gas at room temperature. both are polar covalent compounds. which compound most likely has the strongest intermolecular forces?
a. water
b ammonia

Water has the strongest inter-molecular forces.

Explanation:

As given that water and ammonia both are polar however water is liquid and ammonia is a gas at room temperature.

Let us understand the difference between solid, liquid and gas.

The three states differ from each other due to

a) inter-molecular forces of attraction (the force of attraction between two molecules of same or different substance).

b) the thermal energy of molecules.

In case of solids the inter-molecular forces are maximum and the thermal energy is least. So the molecules are held strong with each other and does not move here and there.

In case of liquid and gas, the inter-molecular forces of attraction are stronger in liquid as compared to gas while thermal energy of gas molecules is more.

In water, the oxygen atom is more electro-negative than nitrogen of ammonia. This makes water molecular more polar.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.

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