There are some structural isomers of the compound ${\mathrm{C}}_2{\mathrm{H}}_4{\mathrm{Cl}}_2$. Draw the displayed formulae of the isomers and name them.

A chemist was investigating the best way to produce $1, 2$-dichloroethane. She reacted ethane with chlorine in the presence of UV light by the following reaction:

${\mathrm{C}}_2{\mathrm{H}}_{6 } \left(\mathrm{g}\right) +2{\mathrm{Cl}}_2 \left(\mathrm{g}\right) \to {\mathrm{C}}_2{\mathrm{H}}_4{\mathrm{CI}}_2 \left(\mathrm{l}\right)+2\mathrm{HCI} \left(\mathrm{g}\right)$

Name the type of reaction.

A chemist was investigating the best way to produce $1, 2$-dichloroethane. She reacted ethene with chlorine in the dark by the following reaction:

${\mathrm{C}}_2{\mathrm{H}}_{4 }\left(\mathrm{g}\right) +2{\mathrm{Cl}}_2\left(\mathrm{g}\right) \to {\mathrm{C}}_2{\mathrm{H}}_4{\mathrm{CI}}_2\left(\mathrm{l}\right)$

Name the type of reaction.