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