DPP

Three samples of the same salts are taken separately. Excess of ${\mathrm{NH}}_4\mathrm{OH}$ gives white precipitate with the first sample. The second sample gives white precipitate with $\mathrm{NaCl}$. The third sample gives black precipitate when ${\mathrm{H}}_2\mathrm{S}$ gas is passed through the solution. The possible salt is

In the borax bead test of ${\mathrm{Co}}^{2+}$, the blue colour of bead is due to the formation of:

Aq. Solution of $\text{'}\mathrm{X}\text{'}$reacts with ${\mathrm{Na}}_3\left[\mathrm{Co}{\left({\mathrm{NO}}_2\right)}_6\right]$ to form yellow precipitate. The cation(s) present in $\text{'}\mathrm{X}\text{'}$ is/are:

Potassium chromate solution is added to aqueous solutions of metal nitrate. The yellow precipitate thus obtained is insoluble in acetic acid. These are subjected to flame test, flame colour of individual precipitate is/are

Which of the following aqueous solution of cation(s) give(s) white precipitate with $\mathrm{NaOH}$ and ${\mathrm{NH}}_4\mathrm{OH}$ solution and formed precipitate is/are further completely dissolved in one of the excess reagent?

Saturated solution of ${\mathrm{SO}}_2$ is heated at $150°\mathrm{C}$ in a closed container. The product obtained is treated with ${\mathrm{BaCl}}_2$ solution. What is/are the most suitable observation(s)?

${\mathrm{Cu}}^{2+}$ and ${\mathrm{Cd}}^{2+}$ can be distinguished by which of the following reagent(s).

White precipitate in test tube "c" and the soluble complex formed from white precipitate with the hypo solution is/are (This question from book is not having information hence the question is reframed as given below).

A salt solution when treated with ammonia forms a white precipitate. On addition of excess ammonia, the precipitate is insoluble. When the same solution is treated with hypo white precipitate is formed; when in excess amount of hypo is completely soluble. When the white precipitate formed from treatment of hypo is heated, it turns black. Identify the white precipitate and its soluble complex.