Which of the following ions will not give a precipitate with $AgNO_3$?

$A$ solution of a salt in dilute $H_2SO_4$ gives a blue color with starch iodide solution. This indicates the presence of which ion?

$A$ 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?

$Na_2CO_3$ cannot be used to identify which of the following ions?

In the chromyl chloride test,the reagent used is

Which reagent below would enable you to remove sulphate ions from a solution containing both sulphate and chloride ions?