School Chemistry Unit Test Prep: 5 Essential Revision MCQs
Here are five revision MCQs on ideas that come up again and again in school chemistry tests.
After the answers, you will see how to plan your last days before the test and use chapter revision on the Dreamers Quiz portal.
How to use these five questions
Do not read the answers first. Keep a blank page and a pencil. Give yourself about one minute per question. A school test is timed, so you should practise in the same way.
Write your choice for each question. Then mark how sure you were: sure, half sure, or guessed. This matters. A correct guess is not knowledge, and it can fail you on the day of the test.
These are sample practice questions based on textbook-level ideas from Class 11 and Class 12. They show you the style of questions to practise. Your own syllabus and your teacher's pattern come first.
The five revision MCQs
Q1. Mole concept. How many moles are present in 36 g of water? The molar mass of water is 18 g/mol.
- 1 mol
- 2 mol
- 3 mol
- 4 mol
Q2. Atomic structure. Which quantum number decides the shape of an orbital?
- Principal quantum number (n)
- Azimuthal quantum number (l)
- Magnetic quantum number (ml)
- Spin quantum number (ms)
Q3. Periodic trends. Which element has the largest atomic radius among Na, Mg, Al and Si?
- Na
- Mg
- Al
- Si
Q4. Ionic equilibrium. A solution of hydrochloric acid has [H+] equal to 10−3 mol/L. What is its pH? Assume the acid ionises completely.
- 1
- 2
- 3
- 11
Q5. Redox reactions. What is the oxidation state of manganese in KMnO4?
- +2
- +4
- +6
- +7
Answers and the reasoning behind them
Look at your page now. Compare each choice with the answer below, and read the reason even when you were right.
| Question | Answer | Idea tested |
|---|---|---|
| Q1 | B | Moles = mass ÷ molar mass |
| Q2 | B | Azimuthal quantum number gives orbital shape |
| Q3 | A | Radius decreases across a period |
| Q4 | C | pH = −log[H+] |
| Q5 | D | Sum of oxidation states in a neutral compound is zero |
Q1 worked out.
- Moles of water = mass ÷ molar mass = 36 ÷ 18 = 2 mol.
- Option A comes from dividing the wrong way round or stopping early. Option D comes from multiplying instead of dividing.
- Always write the units. Grams divided by grams per mole leaves moles, which tells you the step is correct.
Q2. The principal quantum number (n) gives the size and energy level. The azimuthal quantum number (l) gives the shape: l = 0 is an s orbital (spherical), and l = 1 is a p orbital (dumbbell). The magnetic quantum number gives the orientation in space. The spin quantum number describes the electron's spin.
Q3. Na, Mg, Al and Si are in the same period. As you move left to right, the nuclear charge increases while electrons are added to the same shell. The nucleus pulls the outer electrons closer, so the atom becomes smaller. Sodium is on the extreme left, so it is the largest.
Q4. Hydrochloric acid is a strong acid, so it ionises completely. Here [H+] = 10−3 mol/L. Then pH = −log(10−3) = 3. Students who choose 11 have mixed up pH with pOH, which is used for bases. At room temperature, pH + pOH = 14.
Q5. Potassium is +1. Four oxygen atoms are −2 each, which gives −8. The compound is neutral, so: (+1) + x + (−8) = 0. This gives x = +7.
What your answers tell you
Count the questions you got wrong, and also the ones you guessed. Both groups need revision. Now sort each problem into one of three types.
- Concept gap: you did not know the idea, such as which quantum number controls shape. Re-read the chapter in your NCERT textbook and make a short note in your own words.
- Method slip: you knew the idea but missed a step, such as dividing the wrong way in Q1. Redo the question slowly on paper.
- Careless error: you mixed up pH and pOH, or misread the question. Underline the key words in the next set.
Each type needs a different cure. If you only read more pages, you will fix concept gaps but not careless errors.
Preparing for the test with chapter revision
The Dreamers Quiz portal has timed chemistry quizzes for Class 11, Class 12, NEET, JEE and CUET. You pick a class or exam, attempt the set against the clock, and then see your score and the answer key. You can attempt as many times as you like. The portal lists chapter revision before a school test as one of its uses.
Here is a simple plan to follow in the days before your test.
- Make a chapter list. Write down every chapter your teacher has said will be in the test.
- Study first, then test. Spend a short session on one chapter from your textbook and notes. Then attempt a timed set. Testing yourself right after studying shows what did not stay in your head.
- Read the answer key properly. Look at each wrong answer and sort it into concept gap, method slip or careless error, as above.
- Repeat the set. Since attempts are not limited, try the same chapter again after a gap of a day. Compare your two scores. Better still, compare the type of mistakes you made.
- Finish with a mixed session. Near the test, go through several chapters in one sitting, as a real paper does.
Keep a "mistake page" in a notebook. Write each wrong question in one line, with the correct idea beside it. The night before the test, read only this page. It is short, and it is about you.
Common errors in these topics
- Units in mole problems: always write g, mol and g/mol next to numbers. The units show you which step comes next.
- Periodic trends: remember the direction. Across a period, atomic radius decreases. Down a group, it increases.
- pH of acids: find [H+] first. Then take the negative logarithm. Do not read the pH directly from the concentration.
- Oxidation states: write the known ones first (K = +1, O = −2 in most compounds), then solve for the unknown.
Key takeaways
- Attempt practice MCQs in timed conditions before checking the answers.
- Mark guesses separately; a correct guess still needs revision.
- Sort every mistake as a concept gap, method slip or careless error, and fix each one differently.
- Use timed chapter sets on the portal, read the answer key, and repeat the set after a day.
- Keep a one-page list of your own mistakes for the final evening.
Frequently asked questions
How many MCQs should I solve before a unit test?
There is no fixed number. Solve questions chapter by chapter until your mistakes in that chapter stop repeating. Then move to the next chapter.
Can I attempt the same quiz set more than once?
Yes. The portal says you can attempt as many times as you like. Use this to repeat a weak chapter and see whether your score and mistakes improve.
What do I see after finishing a quiz on the portal?
You see your score and the answer key. Use the key to find out why each wrong option was wrong.
Is the portal only for school tests?
No. The portal lists chapter revision before a school test, a quick check after a class, and speed practice for the NEET and CUET MCQ sections.
Should I memorise answers to the sample questions?
No. Questions in your test will be different. Learn the idea behind each answer, such as moles = mass ÷ molar mass, and apply it to new numbers.
What to do next. Try it yourself on the page below.
Chemistry Quiz — Free Timed Chemistry Quizzes →
