Question

1. A student is given the following solutions to use in an experiment that is very much like the one you are about to undertake. List all the possible combinations of cations and anions she can mix together.

Ni²⁺

Cu²⁺

CO₃²⁻

ClO₄⁻

2. Another student mixes the following ions together and gets the following data:

RbCl _(aq)+ Fe(NO₃)_3(aq) → no precipitate

Rb₂SO_3(aq) + Sr(NO₃)_2(aq) → precipitate

What are the possible products when solutions of RbCl and Fe(NO₃)₃ are mixed?

What are the possible products when solutions of Rb₂SO₃ and Sr(NO₃)₂ are mixed?

What is the identity of the precipitate in the second

Answer 1

1) the possible combinations are

i) Ni+2 + ClO4-

ii) Cu+2 + ClO4-

iii) Ni+2 + Co3-2

iv) Cu+2 + CO3^-2

2)3 RbCl (aq) + Fe(NO3)3 (aq) ------------> FeCl3 (aq) + 3 RbNO3(aq)

The possible products are ferric chloride and rubidium nitrate both are water soluble giving no precipitate.

Rb2SO3(aq) + Sr(NO3)2(aq) --------------> SrSO3(s) +2 RbNO3 (aq)

The possiblle products are strontium sulphite and rubidium nitrate. Strontium sulphite is water insolble and thus precipitates.

All nitrate salts are soluble in water.