The $IUPAC$ name of $CH_3COCH_3$ is

Provide the $IUPAC$ name for the following compound.

What is the number of chiral carbon atoms present in $2$-Bromo-$3,4,5$-trimethylhexane?

The correct $IUPAC$ name of the given compound is:

What is the correct $IUPAC$ name of the following structure? Explain.
$CH_3-CH_2-CH(CH_2-CH_3)-CH_2-CH_2-CH(CH_3)-CH_2-CH_3$
$(i)$ $3-$ethyl$-6-$methyloctane
$(ii)$ $3-$methyl$-6-$ethyloctane
$(iii)$ $6-$methyl$-3-$ethyloctane

What is the $IUPAC$ name of crotonyl alcohol?