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When a base is used, then the products are formed by an elimination reaction.

Strong bases such as hydroxides and ethoxides favor E2 reactions, which are the same for the strong and bulky bases like tert-butoxide and DBU. Strong and bulky bases abstract protons from the less hindered sides.

Weak bases such as water favor E1 reactions. When more than one equivalent of a base is used, then the formation of alkyne takes place.

Weak nucleophiles such as water and ethanol favor ${\text{S}}_{\text{N}}\text{1}$reactions, while strong nucleophiles like ethoxides favor ${\text{S}}_{\text{N}}\text{2}$reactions.

Tertiary halides favor ${\text{S}}_{\text{N}}\text{1}$, E1, and E2 reactions, followed by the secondary and primary halides. The reverse case is followed in the case of ${\text{S}}_{\text{N}}\text{2}$ reactions.

Based on all the steps, the organic products formed from each reaction are as follows:

Representation of possible product in reaction a

Representation of possible product in reaction b

Representation of possible product in reaction c

Representation of possible product in reaction d

Representation of possible product in reaction e

Representation of possible product in reaction f

Representation of possible product in reaction g

Representation of possible product in reaction h