What happens to a reaction at equilibrium when the concentration of the PRODUCTS is increased ?

Equilibrium shift to left, favoring the formation of reactants.

Explanation:

Take the equation below as an instance

CaCO3(s) ⇌CaO(s) + CO2(g)

Once, concentration of the PRODUCTS,

CaO(s) and CO2(g) are increased, the equilibrium constant, K remains the same while the equilibrium position shift to the left, favoring the formation of reactant, CaCO3(s)

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.