Since phenol are used as antiseptics this not surprising. Thiols don't have an odor, they have a stench. A very tiny amount of methanethiol is added to natural gas. It is the odor that you associate with natural gas. Since natural gas has no odor of it own, the methanethiol is added so you can detect leaks before explosive concentrations are reached.
Alcohols undergo dehydration, that is, the removal of water.
Depending on the type of alcohol and the temperature of the reaction two different major products are possible. Using an acid catalyst, the major product is going to be toward the carbon with the fewer hydrogens on it. If there is a choice between a carbon with three hydrogens and a carbon with two hydrogens the double bond will form with the carbon with two hydrogens. Notice also in the reaction above that heat is used and a specific temperature is mentioned. At this temperature the major product will be the double bond.