Give the number of stereoisomers of the following compounds.
a. 2-Bromobicyclo `[2.2.1]` heptane or 2-bromo norborane
b. 2-Ethyl-7-bromo `[2.2.1]` heptane or 2-ethyl-7-bromonorborane

Explanation

a. It shows two geometrical isomers. Br can be exo (cis) or endo (trans) to the `C^(7)` bridge, the smallest ring.

b. It shows four geometrical isomers.
i. The `C^(7)` Br can be syn (cis) or and (trans) to the bridge containing the ethyl substituent.
ii. Ethyl group can be exo (cis) or endo (trans) to the Br at `C^(7)` bridge.