$A$ sodium salt on treatment with $MgCl_2$ gives white precipitate only on heating. The anion of the sodium salt is

$A$ substance on treatment with dilute $H_2SO_4$ liberates a colourless gas which produces:
$(i)$ turbidity with baryta water and
$(ii)$ turns acidified dichromate solution green.
The reaction indicates the presence of:

Anion which can react with $dil. H_2SO_4$ is

To a solution of a colourless efflorescent sodium salt, when dilute acid is added, a colourless gas is evolved along with the formation of a white precipitate. Acidified dichromate solution turns green when the colourless gas is passed through it. The sodium salt is

$A$ substance reacts with dilute $H_2SO_4$ to release a colorless gas which $(i)$ turns baryta water turbid and $(ii)$ turns acidic dichromate solution green. This reaction indicates the presence of which of the following?

What is the color of the precipitate formed when phosphate ions react with ammonium molybdate?