Which type of reaction occurs in the following?
2hgo(s) -- 2hg(l) + o2(g)
1. a decomposition reaction in which a metal is reduced
2. an acid-base neutralization reaction to produce oxygen gas a displacement
3. reaction involving two metals a combustion
4. reaction involving burning a metal in oxygen

1. A decomposition reaction in which a metal ion is reduced  

Explanation:

In a decomposition reaction, a single compound is converted into two or more simpler substances.

In this reaction, the oxidation number of Hg decreases from +2 in HgO to 0 in Hg (reduction), so the mercury ion is reduced.

2 is wrong. There are no acids or bases on the reactant side of the equation.

3 is wrong. There are no metals on the reactant side of the equation.

4 is wrong. There is no oxygen on the reactant side of the equation.

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.

tracks, burrows, eggshells, nests, tooth marks, or gastroliths