Week 4 Problem Set
Solution
, AP Chemistry Week 4
Problem Set Solution
Multiple Choice Question
Question 1: Which of the following equations represents the reaction between solid
magnesium hydroxide and aqueous hydrochloric acid?
A) Mg(OH)2(s) + 2HCl(l) → MgCl2(aq) + H2O(l)
B) MgOH(s) + HCl(aq) → MgCl(aq) + 2H2O(l)
C) Mg(OH)2(s) + 2HCl(aq) → MgCl2(aq) + 2H2O(l)
D) Mg(OH)2(s) + HCl(aq) → MgCl2(aq) + H2O(l)
E) MgOH(s) + 2HCl(aq) → MgCl(aq) + 2H2O (l)
Answer: C. This is an acid-base reaction between a strong acid (HCl) and a strong base
(Mg(OH)2). Therefore, the products salt and water. Option C has the correct balanced
equation coefficients. Mg2+ and Cl- combine to form MgCl2.
Question 2: Which of the following represents a process in which a species is reduced?
A) Mg → Mg2+
B) Cl2 → Cl–
C) Ni3+ → Ni4+
D) CO → CO2
E) NO2– → NO3–
Answer: B, chlorine. Mg and Ni3+ lose electrons (oxidation). Similarly, C in CO goes from
+2 to +4 in CO2. It is losing electrons and getting oxidized. The nitrogen atom is also
oxidized. N goes from +3 in NO2- to +7 in NO3-
Question 3: What is the balanced REDOX reaction equation under basic conditions?
A) 2Sb + 3Cl2 + 4OH– → 2SbO+ + 6Cl– + 2H2O
B) 2Sb + 3Cl2 + 2H2O → 2SbO+ + 6Cl– + 4H+
C) 2Sb + 3Cl2 → 2SbO+ + 6Cl–
D) 2Sb + 3Cl2 + 2H2O → 2SbO+ + 6Cl– + 4OH–
E) Sb + Cl2 + 2OH– → SbO+ + 2Cl– + 2H2O
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