# Quiz 2 - Chemical Reactions and Properties of Solutions | Chemical Reactions and Properties of Solutions

## General Chemistry 2 - Quiz 2 - Chemical Reactions and Properties of Solutions

Which of the following is a weak electrolyte?

CH_{3}COOH (acetic acid) is a weak electrolyte because it partially dissociates into CH_{3}COO^{−} and H^{+} ions in solution.

What is the oxidation state of chlorine in KClO_{3}?

In KClO_{3}, potassium has an oxidation state of +1, and oxygen has an oxidation state of -2. The oxidation state of chlorine is calculated as follows:

KClO_{3}: +1 + *x* + 3 x (−2) = 0 ⇒ *x* = +5

Which of the following is a property of a strong acid?

A strong acid completely ionizes in solution, releasing all its H^{+} ions.

Balance the following redox reaction in acidic solution: MnO_{4}^{−} + Fe^{2+} → Mn^{2+} + Fe^{3+}. What is the coefficient for Fe^{2+} when the equation is balanced?

The balanced redox reaction in acidic solution is: MnO_{4}^{−} + 5 Fe^{2+} + 8 H^{+} → Mn^{2+} + 5 Fe^{3+} + 4 H_{2}O

Balance the redox reaction in a basic solution: MnO_{4}^{−} + C_{2}O_{4}^{2−} → MnO_{2 }+ CO_{2}. What is the coefficient of MnO_{2} when the equation is balanced?

The balanced redox reaction in a basic solution is: MnO_{4}^{−} + C_{2}O_{4}^{2−} + 2 H_{2}O → MnO_{2 }+ 2 CO_{2} + 4 OH^{-}

Which solution will have the highest electrical conductivity?

NaCl is a strong electrolyte and completely dissociates into Na^{+} and Cl^{− }ions, providing high electrical conductivity.

What is the ionic strength of a 0.2 M Na_{2}SO_{4} solution?

The ionic strength I is calculated using the formula I = $\frac{1}{2}$ $\sum _{\mathrm{i}=1}^{\mathrm{n}}{\mathrm{c}}_{\mathrm{i}}{{\mathrm{z}}_{\mathrm{i}}}^{2}$

Na_{2}SO_{4} → 2 Na^{+} + SO_{4}^{2-}, therefore:

- Na
^{+ }has c = 2 x 0.2 M = 0.4 M and z = +1 - SO
_{4}^{2-}has c = 0.2 M and z = -2

I = $\frac{1}{2}$ [0.4 x 1 + 0.2 x 4] = 0.6 M

Which of the following best describes the solubility of KNO_{3} in water as temperature increases?

The solubility of most solid solutes, including KNO_{3} (potassium nitrate), in water increases with an increase in temperature.

Which of the following solvents would best dissolve a nonpolar solute like iodine (I_{2})?

Hexane is a nonpolar solvent and is best suited for dissolving nonpolar solutes like iodine (I_{2}), following the "like dissolves like" principle.

Calculate the mole fraction of a solution that contains 2 moles of NaCl and 8 moles of water.

The mole fraction of NaCl is given by $\frac{\mathrm{moles}\mathrm{of}\mathrm{NaCl}}{\mathrm{total}\mathrm{moles}}$ = $\frac{2}{2+8}$ = 0.2