Reactions are shown below,
Reaction 1:
This reaction followed Morkovnikov's rule, because according to this rule hydrogen will go to that carbon which has greater number of hydrogens or fewer number of carbons.
Reaction 2:
This reaction followed Anti-Morkovnikov's rule, and it is opposite to reaction 1.
Reaction 3:
This reaction followed Zaitsev's Rule, according to this rule elimination will yield highly substituted alkene.