Exam-style practice (harder): Chemistry multiple choice
14 harder, exam-style QCE Chemistry Units 3 and 4 multiple-choice questions: pH, Ka, Kw at other temperatures, conductivity curves, the reaction quotient, redox, electrolysis, sacrificial anodes, nomenclature, optical isomers, spectroscopy, yield and back titration. Each is tagged with its question type and every distractor explained. Original practice questions.
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Why this set is harder than a recall quiz
The QCAA Chemistry external assessment expects you to calculate, interpret and apply, not just recall. Its multiple-choice questions typically give data, a reaction or a scenario, and each wrong option is the answer you get from one specific slip.
These 14 questions follow that design. They are original practice questions written by ExamExplained, not from any QCAA paper. Each explanation begins with a Type tag and names the slip behind every wrong option.
Write the relationship before the numbers (Q = [products] / [reactants], I = Q / t, n = cV) and carry units. Most distractors are complete answers to a slightly wrong calculation.
The question types
| Type | What it looks like | Typical trap |
|---|---|---|
| Calculation | pH of bases, Ka, reaction quotient, electrolysis current, yield, back titration | Missing a factor of 2, minutes for seconds, inverted expressions, excess treated as reacted |
| Data interpretation | Conductivity curves, electrochemical series, spectra | Thinking ions disappear at equivalence; choosing a less reactive metal as a sacrificial anode |
| Concept application | Neutrality at other temperatures, redox roles, naming, chirality, denaturation | pH 7 as the definition of neutral; gaining oxygen as reduction |
Question map
| Q | Type | Syllabus area |
|---|---|---|
| 1 | Calculation | Unit 3: pH of a strong base |
| 2 | Calculation | Unit 3: Ka from pH |
| 3 | Concept application | Unit 3: Kw and neutrality |
| 4 | Data interpretation | Unit 3: conductivity during a titration |
| 5 | Calculation | Unit 3: reaction quotient |
| 6 | Concept application | Unit 3: oxidation numbers and redox roles |
| 7 | Calculation | Unit 3: electrolysis |
| 8 | Data interpretation | Unit 3: sacrificial anodes |
| 9 | Concept application | Unit 4: IUPAC naming |
| 10 | Concept application | Unit 4: optical isomers |
| 11 | Data interpretation | Unit 4: mass spectrometry and IR |
| 12 | Calculation | Unit 4: percentage yield and atom economy |
| 13 | Concept application | Unit 4: protein denaturation |
| 14 | Calculation | Unit 3: back titration |
Five checks before you commit
- How many H⁺ or OH⁻ per formula unit? Ba(OH)₂ gives two hydroxide ions.
- Q versus K. If Q is larger than K, the reaction shifts left; if smaller, it shifts right.
- Seconds, not minutes. Faraday calculations use Q = It with t in seconds.
- Yield versus atom economy. Yield compares actual with theoretical product; atom economy compares the mass of desired product with the total mass of reactants.
- Back titrations measure what is left over. Subtract the excess from the total to find what reacted.
Choosing a sacrificial anode that is "less reactive" so it will not corrode. The sacrificial metal must be MORE reactive (a stronger reductant) than iron, so that it corrodes instead.
What to do next
- Review the exam structure and timing in the QCE Chemistry external assessment strategy.
- Work through the QCE Chemistry external assessment preparation guide.
- Then complete a QCAA past paper and mark it against its published marking guide.
Sources & how we know this
- chemistry
- qce-chemistry
- multiple-choice
- external-assessment
- exam-technique
- practice-questions
- units-3-4