Acid–base neutralization reactions Original Scenario-Based Practice

Questions

1. 1.

   A floating botanical sanctuary uses a chemical neutralization unit to convert acidic runoff into crystalline agricultural fertilizer. In this process, 250.0 mL of 1.60 M nitric acid, $\text{HNO}_3$, is treated with an excess of solid calcium hydroxide, $\text{Ca(OH)}_2$, according to the equation $2\text{HNO}_3(aq) + \text{Ca(OH)}_2(s) \rightarrow \text{Ca(NO}_3)_2(aq) + 2\text{H}_2\text{O}(l)$. After the reaction reaches completion and the resulting mixture is evaporated to dryness, what theoretical mass of anhydrous calcium nitrate, $\text{Ca(NO}_3)_2$ (molar mass = 164.10 g/mol), is recovered?

   • A) 65.6 g
   • B) 16.4 g
   • C) 32.8 g
   • D) 82.1 g
2. 2.

   In an atmospheric humidity recycling module aboard an orbital space station, an accidental cross-flow valve leakage blends 120.0 mL of 0.500 M sulfuric acid, $\text{H}_2\text{SO}_4$, with 80.0 mL of 1.25 M sodium hydroxide, $\text{NaOH}$, in a neutralization chamber according to the reaction $\text{H}_2\text{SO}_4(aq) + 2\text{NaOH}(aq) \rightarrow \text{Na}_2\text{SO}_4(aq) + 2\text{H}_2\text{O}(l)$. Assuming the reaction proceeds completely to stoichiometric exhaustion of the limiting reactant, which reactant remains in excess and how many moles of it remain unneutralized?

   • A) $0.0100\text{ mol of }\text{H}_2\text{SO}_4$
   • B) $0.0400\text{ mol of }\text{NaOH}$
   • C) $0.0200\text{ mol of }\text{H}_2\text{SO}_4$
   • D) $0.0500\text{ mol of }\text{NaOH}$
3. 3.

   A deep-space terraforming vessel synthesizes atmospheric moisture, but an unexpected catalytic malfunction contaminates a storage reservoir with hydrochloric acid, $\text{HCl}$. To determine the extent of contamination, the vessel's automated diagnostic unit titrates a 50.0 mL sample of this reservoir water with a 0.250 M barium hydroxide solution, $\text{Ba(OH)}_2$. The sample reaches complete neutralization when precisely 32.0 mL of the $\text{Ba(OH)}_2$ solution is dispensed according to the reaction $2\text{HCl}(aq) + \text{Ba(OH)}_2(aq) \rightarrow \text{BaCl}_2(aq) + 2\text{H}_2\text{O}(l)$. What is the molar concentration of hydrochloric acid in the contaminated reservoir?

   • A) 0.080 M
   • B) 0.160 M
   • C) 0.320 M
   • D) 0.640 M
4. 4.

   During an expedition inside an abandoned bioluminescent cavern, an automated exploration drone encounters an acidic pool containing 40.0 L of 0.750 M phosphoric acid, $\text{H}_3\text{PO}_4$, that threatens to dissolve rare mineral formations. The drone initiates neutralization using a stored supply of 1.50 M sodium hydroxide solution, $\text{NaOH}$, according to the equation $\text{H}_3\text{PO}_4(aq) + 3\text{NaOH}(aq) \rightarrow \text{Na}_3\text{PO}_4(aq) + 3\text{H}_2\text{O}(l)$. What minimum volume of this sodium hydroxide solution is required to achieve complete neutralization of the pool?

   • A) 20.0 L
   • B) 60.0 L
   • C) 90.0 L
   • D) 180.0 L
5. 5.

   A subterranean geothermal research outpost experiences a drainage line rupture, spilling 250 L of wastewater containing 0.40 M sulfuric acid, $\text{H}_2\text{SO}_4$, into its containment sump. To neutralize the spill before it corrodes the facility's bedrock anchors, the emergency team treats the liquid with solid calcium hydroxide, $\text{Ca(OH)}_2$, according to the equation $\text{H}_2\text{SO}_4(aq) + \text{Ca(OH)}_2(s) \rightarrow \text{CaSO}_4(s) + 2\text{H}_2\text{O}(l)$. Given that the molar mass of $\text{Ca(OH)}_2$ is 74.10 g/mol, what minimum mass of pure calcium hydroxide is required for complete neutralization?

   • A) 3.71 kg
   • B) 7.41 kg
   • C) 14.8 kg
   • D) 5.61 kg

Answers and step-by-step solutions appear after you finish the test.