Which of the following statements is false :-

$\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}$ has a $\mathrm{Cr}-\mathrm{O}-\mathrm{Cr}$ bond

$\mathrm{CrO}_{4}^{2-}$ is tetrahedral in shape

$\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ is a primary standard in volumetry

$\mathrm{Na}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$ is less soluble than $\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7}$