# Problem: A 100.0-mL aliquot of 0.200 M aqueous potassium hydroxide is mixed with 100.0 mL of 0.200 M aqueous magnesium nitrate. What mass of precipitate is produced?

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###### FREE Expert Solution

We first need to determine the products that will form when potassium hydroxide, KOH, and magnesium nitrate, Mg(NO3)2, are mixed. There will be a double displacement reaction, where KOH and Mg(NO3)2 will switch ions. This means KNO3 and Mg(OH)2 will form.

According to solubility rules, nitrates are soluble while hydroxides are insoluble, except when paired with Group 1A ions and NH4+. This means KNO3 is soluble and will dissolve in solution while Mg(OH)2 is insoluble and will precipitate out. The chemical reaction is:

2 KOH(aq) + Mg(NO3)2(aq) → 2 KNO3(aq) + Mg(OH)2(s)

We then need to determine which between KOH and Mg(NO3)2 is the limiting reactant. The limiting reactant will form the less amount of Mg(OH)2.

###### Problem Details

A 100.0-mL aliquot of 0.200 M aqueous potassium hydroxide is mixed with 100.0 mL of 0.200 M aqueous magnesium nitrate. What mass of precipitate is produced?