Draw the products of the following reactions. If the products can exist as stereoisomers show what stereoisomers are formed.
$
\text { a.cis }-2-\text { pentene }+\mathrm{Br}_2 / \mathrm{CH}_2 \mathrm{Cl}_2
$
$
\text { b.trans }-2-\text { pentene }+\mathrm{Br}_2 / \mathrm{CH}_2 \mathrm{Cl}_2
$
$
\text { c.1-butene }+\mathrm{HCl}
$
$
\text { d.methylcyclohexene }+\mathrm{HBr}
$