When two substances at room temperature are combined, the product feels HOT. What kind of reaction is this?

The correct answer is - exothermic reaction.

Explanation:

Exothermic reactions are the reaction that releases energy into the surrounding and does not require energy to take place due to the total energy of the reactants the total energy of the products is more than tthe total energy of the products. It releases energy usually as heat or light with the product.

In the given condition of room temperature mixing two substance produces hot products, fits with the explanation given above, therefore, it is an exothermic reaction.

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.