E2 is not particularly sensitive to steric hindrance because the base is forming a bond to a hydrogen which is typically more exposed. The prefered geometry for E2 has the LG and the H that is removed in an Anti conformation. Think about how this reaction might work - it's an SN2 mechanism that takes a couple of steps. Grignard reagents are carbanions that are strong bases, and react with ketones and aldehydes as nucleophiles. Chapter 8 Chapter 8 concerns alcohols and ethers - know how to name these types of compounds.
Acidity refers to the ease with which a compound donates a hydrogen ion.
Chlorophenol is more acidic than phenol for the same reason. Likewise, if the anion can spread the charge around through resonance structures it will be more stable. Phenol is much more acidic than cyclohexanol because of resonance stabilization of the negative charge. For our purposes, this refers to a change in the number of pi-bonds. These reagents don't break carbon-carbon bonds, so tertiary alcohols don't react and secondary alcohols cannot be oxidized to carboxylic acids.