Which of the following statements is false?

$\displaystyle \mathrm{CrO}_4^{2-}$ is tetrahedral in shape

$\displaystyle \mathrm{Cr}_2 \mathrm{O}_7^{2-}$ has a $\displaystyle \mathrm{Cr}-\mathrm{O}-\mathrm{Cr}$ bond

$\displaystyle \mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7$ is a primary standard in volumetry

$\displaystyle \mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7$ is less soluble than $\displaystyle \mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$