In how many of the following reactions, one of the products is obtained as a yellow precipitate?

${\mathrm{Ba}}^{2+}+{\mathrm{CrO}}_4^{2-}⟶$product

${\mathrm{Hg}}^{2+}+{\mathrm{Co}}^{2+}+{\mathrm{SCN}}^{\mathrm{\Theta }}⟶$product

${\mathrm{NH}}_4^{\oplus }+{\left[{\mathrm{PtCl}}_6\right]}^{2-} \to$product

${\mathrm{Ag}}^{\oplus }+{\mathrm{CrO}}_4^{2-}⟶$product

${\mathrm{NH}}_4^{\oplus }+{\left[\mathrm{Co}{\left({\mathrm{NO}}_2\right)}_6\right]}^{3-}$$\to$product