Reactions in Aqueous Solutions — Hard Practice Quiz

A Chemistry cheat sheet for Reactions in Aqueous Solutions — every key formula with its symbols defined — plus a hard-level practice quiz to test recall.

Practice quiz

1. A $0.5 \text{ M}$ solution of copper(II) nitrate is diluted by adding $200 \text{ mL}$ of water to $100 \text{ mL}$ of the original solution. If a piece of zinc metal is then added to the diluted solution, what is the final molarity of the $Zn^{2+}$ ions in the solution after the displacement reaction goes to completion, assuming zinc is in excess?

   • $0.125 \text{ M}$
   • $0.167 \text{ M}$
   • $0.250 \text{ M}$
   • $0.500 \text{ M}$

   Answer: $0.167 \text{ M}$

2. A $0.1 \text{ M}$ solution of $Fe(NO_3)_2$ is mixed with an equal volume of a $0.1 \text{ M}$ solution of $AgNO_3$. If a piece of solid copper is added to this mixture, which metal ions will be displaced, and what will be the molarity of the newly formed copper(II) ions in the final solution, assuming the reaction goes to completion?

   • $Fe^{2+}$ ions are displaced; final $[Cu^{2+}] = 0.05 \text{ M}$
   • $Ag^+$ ions are displaced; final $[Cu^{2+}] = 0.025 \text{ M}$
   • Both $Fe^{2+}$ and $Ag^+$ ions are displaced; final $[Cu^{2+}] = 0.075 \text{ M}$
   • No ions are displaced; final $[Cu^{2+}] = 0 \text{ M}$

   Answer: $Ag^+$ ions are displaced; final $[Cu^{2+}] = 0.025 \text{ M}$

3. A solution of unknown molarity $M_1$ and volume $V_1$ is diluted by adding water until its volume is $3V_1$. This diluted solution is then further diluted by taking half of its volume and adding enough water to make the final volume $4V_1$. What is the final molarity of the solution in terms of $M_1$?

   • $M_1/4$
   • $M_1/6$
   • $M_1/8$
   • $M_1/12$

   Answer: $M_1/8$

4. $250 \text{ mL}$ of a $0.2 \text{ M}$ solution of $Ni(NO_3)_2$ is reacted with an excess of solid aluminum. What mass of nickel metal is produced? (Atomic mass of Ni is $58.69 \text{ g/mol}$)

   • $1.956 \text{ g}$
   • $2.935 \text{ g}$
   • $4.402 \text{ g}$
   • $5.869 \text{ g}$

   Answer: $2.935 \text{ g}$

5. You have $500 \text{ mL}$ of a $0.8 \text{ M}$ solution of $NaCl$. To what final volume must this solution be diluted to achieve a molarity that is one-fifth of its original concentration?

   • $1000 \text{ mL}$
   • $1250 \text{ mL}$
   • $2000 \text{ mL}$
   • $2500 \text{ mL}$

   Answer: $2500 \text{ mL}$

6. A $200 \text{ mL}$ solution of $0.15 \text{ M}$ $Fe(NO_3)_2$ is reacted with $100 \text{ mL}$ of a $0.2 \text{ M}$ $AgNO_3$ solution. If a piece of solid copper is added to the mixture, what is the final molarity of $Fe^{2+}$ ions in the solution after all possible displacement reactions have occurred?

   • $0 \text{ M}$
   • $0.05 \text{ M}$
   • $0.1 \text{ M}$
   • $0.15 \text{ M}$

   Answer: $0.1 \text{ M}$

7. A solution of molarity $M$ is diluted by adding water such that its final volume is $V_f$. If the number of moles of solute remains constant, and the final molarity is $M/4$, what is the ratio of the initial volume $V_i$ to the final volume $V_f$?

   • $1:1$
   • $1:2$
   • $1:4$
   • $4:1$

   Answer: $1:4$

8. A $50 \text{ mL}$ solution of $0.2 \text{ M}$ $Sn(NO_3)_2$ is mixed with $50 \text{ mL}$ of a $0.3 \text{ M}$ $AgNO_3$ solution. A piece of solid copper is added to the mixture. What is the final molarity of $Cu^{2+}$ ions in the solution after all possible displacement reactions have occurred, assuming copper is in excess?

   • $0.015 \text{ M}$
   • $0.030 \text{ M}$
   • $0.075 \text{ M}$
   • $0.150 \text{ M}$

   Answer: $0.075 \text{ M}$

9. You have $200 \text{ mL}$ of a $0.4 \text{ M}$ $KCl$ solution and $300 \text{ mL}$ of a $0.6 \text{ M}$ $KCl$ solution. These two solutions are mixed. Then, $150 \text{ mL}$ of this mixture is taken and diluted to a final volume of $500 \text{ mL}$. What is the final molarity of the $KCl$ solution?

   • $0.104 \text{ M}$
   • $0.156 \text{ M}$
   • $0.260 \text{ M}$
   • $0.520 \text{ M}$

   Answer: $0.156 \text{ M}$

10. Consider three metals X, Y, and Z. Metal X can displace $Y^{2+}$ ions from solution. Metal Y can displace $Z^{2+}$ ions from solution. Metal Z cannot displace $X^{2+}$ ions from solution. Based on this information, which of the following statements is true regarding the relative reactivity of the metals?

    • Metal Z is more reactive than Metal X.
    • Metal Y is the least reactive among the three.
    • Metal X is the most reactive among the three.
    • Metal Z can displace $Y^{2+}$ ions from solution.

    Answer: Metal X is the most reactive among the three.