Question

Why 5-Bromo 5-methoxy hexan-2-ol but not 2-Bromo 2-methoxy hexan-5-ol

Answer 1

Actually, hydrocarbons are very choosy.
They have preferences of giving some substituent/functional group high positions and some low.
The suffix -ol refers to the alcohol group and has a preference of getting the lowest position possible, except in some cases.

I'll list down the functional groups and substituents in their preference order for your reference later.

Hope this helps...