Elimination vs substitution: secondary substrate

[@nicksahloby4097]

For the reaction at 7:05: on what basis did we rule out SN1 and SN2?
For the reaction at 10:20: why are the electrons on the carbonyl more nucleophilic?

[@PrinceSharma-xf7pm]

At 7:05 heat is given and high temperature favours elimination over substitution :)