Problem 25 - Chemistry: The Central Science

Question

Which ions remain in solution, unreacted, after each of the following pairs of solutions is mixed? (a) potassium carbonate and magnesium sulfate (b) lead nitrate and lithium sulfide (c) ammonium phosphate and calcium chloride

Step-by-Step Solution

Answer

(a) The remaining ions in the solution after mixing potassium carbonate and magnesium sulfate are K\(^+\) and SO4\(^{2-}\). (b) The remaining ions in the solution after mixing lead nitrate and lithium sulfide are Li\(^+\) and NO3\(^-\). (c) The remaining ions in the solution after mixing ammonium phosphate and calcium chloride are NH4\(^+\) and Cl\(^-\).

Step 1: (a) Potassium Carbonate and Magnesium Sulfate

Potassium carbonate has the formula K2CO3 and magnesium sulfate has the formula MgSO4.

Step 2: (b) Lead Nitrate and Lithium Sulfide

Lead nitrate has the formula Pb(NO3)2, and lithium sulfide has the formula Li2S.

Step 3: (c) Ammonium Phosphate and Calcium Chloride

Ammonium phosphate has the formula (NH4)3PO4, and calcium chloride has the formula CaCl2. **Step 2: Identify the possible products formed when these reactants are combined**

Step 4: (a) Potential products from Potassium Carbonate and Magnesium Sulfate reaction

When K2CO3 and MgSO4 react, they can form potassium sulfate (K2SO4) and magnesium carbonate (MgCO3).

Step 5: (b) Potential products from Lead Nitrate and Lithium Sulfide reaction

When Pb(NO3)2 and Li2S react, they can form lead sulfide (PbS) and lithium nitrate (LiNO3).

Step 6: (c) Potential products from Ammonium Phosphate and Calcium Chloride reaction

When (NH4)3PO4 and CaCl2 react, they can form ammonium chloride (NH4Cl) and calcium phosphate (Ca3(PO4)2). **Step 3: Determine whether these products would precipitate or remain in solution**

Step 7: (a) Precipitation from Potassium Carbonate and Magnesium Sulfate reaction

In this case, MgCO3 would form a precipitate, while K2SO4 would remain in the solution.

Step 8: (b) Precipitation from Lead Nitrate and Lithium Sulfide reaction

In this case, PbS would form a precipitate, and LiNO3 would remain in the solution.

Step 9: (c) Precipitation from Ammonium Phosphate and Calcium Chloride reaction

In this case, Ca3(PO4)2 would form a precipitate, and NH4Cl would remain in the solution. **Step 4: Write the remaining ions that stay in the solution and do not precipitate**

Step 10: (a) Ions remaining in solution after Potassium Carbonate and Magnesium Sulfate reaction

The remaining ions in the solution are K+ and SO4^2-.

Step 11: (b) Ions remaining in solution after Lead Nitrate and Lithium Sulfide reaction

The remaining ions in the solution are Li+ and NO3^-.

Step 12: (c) Ions remaining in solution after Ammonium Phosphate and Calcium Chloride reaction

The remaining ions in the solution are NH4+ and Cl^-.