Question

multiple choice
use the following information to answer the next question.
the following pairs of solutions are mixed:

1. libr(aq) and zn(no₃)₂(aq)
2. mgso₄(aq) and srcl₂(aq)
3. nh₄no₃(aq) and k₂so₄(aq)
4. na₂s(aq) and fe(no₃)₃(aq)
5. which pair(s) of solutions would produce a precipitate when mixed?

1 and 4
2, 3 and 4
1, 2 and 3
2 and 4

Explanation:

Step1: Analyze pair 1

LiBr(aq) + Zn(NO₃)₂(aq): Lithium bromide and zinc nitrate will not form a precipitate as lithium salts and nitrate salts are generally soluble in water.

Step2: Analyze pair 2

MgSO₄(aq) + SrCl₂(aq): Magnesium sulfate and strontium chloride react to form strontium sulfate (SrSO₄) which is insoluble and will precipitate out. The reaction is MgSO₄(aq)+SrCl₂(aq)→MgCl₂(aq)+SrSO₄(s).

Step3: Analyze pair 3

NH₄NO₃(aq) + K₂SO₄(aq): Ammonium nitrate and potassium sulfate will not form a precipitate since ammonium salts and potassium salts are soluble in water.

Step4: Analyze pair 4

Na₂S(aq) + Fe(NO₃)₃(aq): Sodium sulfide and iron(III) nitrate react to form iron(III) sulfide (Fe₂S₃) which is insoluble and will precipitate. The reaction is 3Na₂S(aq)+2Fe(NO₃)₃(aq)→6NaNO₃(aq)+Fe₂S₃(s).

Answer:

2 and 4