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

Which anion's aqueous solution gives a white precipitate with $AgNO_3$,which is soluble in excess $NH_4OH$?

$P_{(Coloured \ Solution)} + BaCl_2 \to Q \downarrow_{(White)} + R_{(Coloured \ Solution)}$
Then salt $P$ in above reaction is

Which ion's salt solution produces a violet layer when chlorine water and chloroform are added?

In a test tube containing a salt, a few drops of dilute $\text{H}_2\text{SO}_4$ were added, which gave colourless vapours having the smell of vinegar. The vapours turned the blue litmus paper red. Identify the correct anion from the following:

Which of the following anions cannot be easily removed from its aqueous solution by precipitation?