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

1

Which of the following is a weak electrolyte?

CH3​COOH (acetic acid) is a weak electrolyte because it partially dissociates into CH3COO and H+ ions in solution.

2

What is the oxidation state of chlorine in KClO3?

In KClO3​, potassium has an oxidation state of +1, and oxygen has an oxidation state of -2. The oxidation state of chlorine is calculated as follows:
KClO3: +1 + x + 3 x (−2) = 0 ⇒ x = +5

3

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

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

4

Balance the following redox reaction in acidic solution: MnO4 + Fe2+ → Mn2+ + Fe3+. What is the coefficient for Fe2+ when the equation is balanced?

The balanced redox reaction in acidic solution is: MnO4 + 5 Fe2+ + 8 H+ → Mn2+ + 5 Fe3+ + 4 H2O

5

Balance the redox reaction in a basic solution: MnO4 + C2O42− → MnO2 + CO2​. What is the coefficient of MnO2 when the equation is balanced?

The balanced redox reaction in a basic solution is: MnO4 + C2O42− + 2 H2O → MnO2 + 2 CO2 + 4 OH-

6

Which solution will have the highest electrical conductivity?

NaCl is a strong electrolyte and completely dissociates into Na+ and Clions, providing high electrical conductivity.

7

What is the ionic strength of a 0.2 M Na2SO4 solution?

The ionic strength I is calculated using the formula I = $\frac{1}{2}$

Na2SO4 → 2 Na+ + SO42-, therefore:

• Nahas c = 2 x 0.2 M = 0.4 M and z = +1
• SO42- has c = 0.2 M and z = -2

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

8

Which of the following best describes the solubility of KNO3​ in water as temperature increases?

The solubility of most solid solutes, including KNO3​ (potassium nitrate), in water increases with an increase in temperature.

9

Which of the following solvents would best dissolve a nonpolar solute like iodine (I2​)?

Hexane is a nonpolar solvent and is best suited for dissolving nonpolar solutes like iodine (I2​), following the "like dissolves like" principle.

10

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  =  = 0.2