What are alkoxide ion and alkyl bromide?

An alkoxide is the salt of an alcohol; an alkyl bromide is simply ##C_nH_(2n+1)Br##

Alcohols are very weak acids, but can react with alkali metals to give alkoxides:

##ROH(l) + Na(s) rarr RO^(-)Na^+(s) + 1/2H_2(g)uarr##

Here the alkoxide is the sodium salt of the alcohol. An alkyl bromide is simply an alkane substituted by 1 or more bromine atoms:

##C_nH_(2n+1)Br##