Statement 1 : The double bond in ${\mathrm{C}}_2$ molecule consists of both $\mathrm{\pi }-\mathrm{bonds}.$

Statement 2 : Four electrons are present in two $\mathrm{\pi }-\mathrm{bonding} \mathrm{molecular} \mathrm{orbitals} \mathrm{in} {\mathrm{C}}_2.$

Both are true statements 

$\begin{array}{l}{\mathrm{C}}_2:{\left(\mathrm{\sigma }1\mathrm{s}\right)}^2{\left(\mathrm{\sigma }*1\mathrm{s}\right)}^2{\left(\mathrm{\sigma }2\mathrm{s}\right)}^2{\left(\mathrm{\sigma }*2\mathrm{s}\right)}^2\left(\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2\right)\mathrm{or}\\ \mathrm{KK}{\left(\mathrm{\sigma }2\mathrm{s}\right)}^2{\left(\mathrm{\sigma }*2\mathrm{s}\right)}^2\left(\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2\right)\end{array}$

The bond order of ${\mathrm{C}}_2\mathrm{is}1/2\left(8-4\right)=2\mathrm{and}{\mathrm{C}}_2$ should be diamagnetic. It is important to note that double bond in ${\mathrm{C}}_2$ consists of both pi bonds because of the presence of four electrons in two pi molecular orbitals. In most of the other molecules a double bond is made up of a sigma bond and a pi bond.