The colour of the salts are as follows,

${\mathrm{SrSO}}_4$- white
$\mathrm{Mg}\left({\mathrm{NH}}_4\right){\mathrm{PO}}_4$ - white
${\mathrm{BaCrO}}_4$ - yellow
$\mathrm{Mn}(\mathrm{OH}{)}_2$ - white
${\mathrm{PbSO}}_4$ - white
${\mathrm{PbCrO}}_4$ - yellow
$\mathrm{AgBr}$ - pale yellow
${\mathrm{PbI}}_2$ - yellow
${\mathrm{CaC}}_2{\mathrm{O}}_4$ - white

$\left[\mathrm{Fe}(\mathrm{OH}{)}_2\left({\mathrm{CH}}_3\mathrm{COO}\right)\right]$ – Brown Red

Hence the number of salts which are white in colour is $5$.