Question

In the qualitative analysis scheme for metal ions, how are the Analytical Group III cations separated from the cations of Analytical Groups IV and V?

	a.	by addition of H2S in basic solution, forming insoluble metal sulfides or hydroxides
	b.	by addition of HCl, forming insoluble metal chlorides
	c.	by addition of H2SO4, forming insoluble metal sulfates
	d.	by addition of (NH4)2CO3 or (NH4)3PO4, forming insoluble metal carbonates or phosphates
	e.	by addition of H2S in acidic solution, forming insoluble metal sulfides

Answer 1

a

Answer-

Group III: cations of this group are cobalt(II).

Ammonia solution is added until the solution becomes basic. The trivalent cations from respective insoluble hydroxide and precipitate out.

Then upon addition of Ammonium sulfide , S2- reacts with divalent cations to form respective sulfides which is precipitated.

Ammonium sulfide can be generated in the solution by adding ammonium chloride and passing H2S gas.

Group III: cations of this group are cobalt(II).

Ammonia solution is added until the solution becomes basic. The trivalent cations from respective insoluble hydroxide and precipitate out.

Then upon addition of Ammonium sulfide , S2- reacts with divalent cations to form respective sulfides which is precipitated.