Chapter 8, Problem 146QP

Compare the molecular shape around each carbon atom and $\text{H}-\text{C}-\text{C}$ bond angles in ${\text{C}}_{\text{2}}{\text{H}}_{\text{6}}\text{,}{\text{C}}_{\text{2}}{\text{H}}_{\text{4}}\text{,}\text{and}{\text{C}}_{\text{2}}{\text{H}}_{\text{2}}\text{.}$ How are these compounds classified?