Of the reactions listed below, which one is NOT a combination reaction? A) C + O2 => CO2 B) 2Mg + O2 => 2MgO C) 2N2 + 3H => 2NH3 D) CaO + H2O => Ca(OH)2 E) 2CH4 + 4O2 => 2CO2 + 4H2O

E

Explanation:

A combination reaction is one in which two elements or two compounds react to give a new single compound

Hence, what we are expecting on the reactant side is only a single product and not a mixture of products

For the first reaction, we had two elements giving a single product

For the second reaction, we had same

For the third, we had same

For the fourth, we had two compounds reacting to give a singe new product

While in the last, we had two different products which means it does not follow the definition of a combination reaction and that makes it our answer

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.

i think it's c. i'm not sure but i think so.