Chemistry MCQs for PPSC, FPSC & SST Tests with Answers and Explanations
Chemistry MCQs appear in almost every science-based recruitment test in Pakistan. PPSC Lecturer Chemistry, SST Science, School Educator, FPSC Lecturer and the Everyday Science section of one-paper tests all draw questions from the same core areas: atomic structure, the periodic table, chemical bonding, acids and bases, and organic chemistry.
Many candidates memorize hundreds of random questions and still lose marks, because examiners rarely repeat the exact wording. They repeat the concept. This guide groups Chemistry MCQs by topic and adds a short explanation to every answer. If you understand the reason behind an answer, you can solve any version of that question.
Which Tests Include Chemistry MCQs?
You will meet Chemistry questions in these tests:
- PPSC Lecturer Chemistry: The entire subject portion of the paper tests Chemistry at graduate and master’s level.
- SST Science and School Educator Science: These papers cover school-level Chemistry alongside Physics and Biology.
- FPSC Lecturer and Subject Specialist tests: These cover advanced topics, especially physical and organic Chemistry.
- PPSC, FPSC and NTS one-paper tests: The Everyday Science section regularly asks about common chemicals, acids, alloys and gases.
- University entry tests: Science-based admission tests also include a Chemistry section.
Key Topics You Must Cover
Before you start practicing, know where the questions come from. Most Chemistry MCQs fall into seven areas:
- Atomic structure and discoveries
- The periodic table and periodic properties
- Chemical bonding
- Gas laws and states of matter
- Acids, bases and salts
- Common compounds, alloys and industrial chemistry
- Organic chemistry basics
The MCQs below follow the same order, so you can revise one topic at a time.
Atomic Structure MCQs
1. Who discovered the electron?
A) Ernest Rutherford
B) J.J. Thomson
C) James Chadwick
D) Niels Bohr
Answer: B) J.J. Thomson
Thomson discovered the electron in 1897 through his cathode ray experiments. Candidates often confuse him with Rutherford, who proposed the nuclear model of the atom.
2. Who discovered the neutron?
A) James Chadwick
B) J.J. Thomson
C) Henri Becquerel
D) Dalton
Answer: A) James Chadwick
Chadwick discovered the neutron in 1932. The neutron carries no charge, which is why scientists found it later than the electron and proton.
3. Atoms of the same element with different mass numbers are called:
A) Isobars
B) Isotones
C) Isotopes
D) Isomers
Answer: C) Isotopes
Isotopes share the same atomic number but have different numbers of neutrons. Protium, deuterium and tritium are the three isotopes of hydrogen.
4. What is the atomic number of carbon?
A) 12
B) 6
C) 8
D) 14
Answer: B) 6
The atomic number equals the number of protons. Carbon has 6 protons, while 12 is its most common mass number. Examiners often place both numbers in the options to test this difference.
5. Who discovered radioactivity?
A) Marie Curie
B) Henri Becquerel
C) Rutherford
D) Max Planck
Answer: B) Henri Becquerel
Becquerel discovered radioactivity in 1896 while studying uranium salts. Marie Curie later expanded this work and discovered polonium and radium.
Periodic Table MCQs
6. The modern periodic table arranges elements according to their:
A) Atomic mass
B) Atomic number
C) Number of neutrons
D) Density
Answer: B) Atomic number
Mendeleev arranged elements by atomic mass. Henry Moseley later showed that atomic number gives a more accurate order, and the modern periodic law follows his work.
7. Which element has the highest electronegativity?
A) Oxygen
B) Chlorine
C) Fluorine
D) Nitrogen
Answer: C) Fluorine
Fluorine attracts shared electrons more strongly than any other element. Its value on the Pauling scale is about 4.0.
8. Noble gases belong to which group of the periodic table?
A) Group 1
B) Group 17
C) Group 2
D) Group 18
Answer: D) Group 18
Noble gases such as helium, neon and argon have complete outer shells. This structure makes them very unreactive.
9. Which is the lightest element?
A) Helium
B) Hydrogen
C) Lithium
D) Oxygen
Answer: B) Hydrogen
Hydrogen has one proton and usually no neutron. This gives it the lowest atomic mass of all elements.
10. Which non-metal exists as a liquid at room temperature?
A) Bromine
B) Iodine
C) Chlorine
D) Sulphur
Answer: A) Bromine
Bromine is the only non-metal that is liquid at room temperature. Mercury is the liquid metal, and examiners often pair these two facts in the same paper.
11. What is the most abundant element in the Earth’s crust?
A) Silicon
B) Aluminium
C) Oxygen
D) Iron
Answer: C) Oxygen
Oxygen makes up nearly half of the Earth’s crust by mass. Aluminium is the most abundant metal in the crust, which is a separate question.
Chemical Bonding MCQs
12. What type of bond holds sodium chloride (NaCl) together?
A) Covalent bond
B) Ionic bond
C) Metallic bond
D) Hydrogen bond
Answer: B) Ionic bond
Sodium transfers one electron to chlorine. The resulting positive and negative ions attract each other and form an ionic bond.
13. Ice floats on water because:
A) Ice is denser than water
B) Ice has a lower density than water
C) Ice contains air
D) Water has high viscosity
Answer: B) Ice has a lower density than water
Hydrogen bonds arrange water molecules into an open structure when water freezes. This structure takes up more space, so ice becomes less dense than liquid water.
14. A covalent bond forms when atoms:
A) Transfer electrons
B) Share electrons
C) Lose protons
D) Gain neutrons
Answer: B) Share electrons
Atoms share electron pairs in a covalent bond. Water, methane and carbon dioxide all contain covalent bonds.
Gas Laws and States of Matter MCQs
15. According to Boyle’s law, at constant temperature the volume of a gas is:
A) Directly proportional to pressure
B) Inversely proportional to pressure
C) Independent of pressure
D) Directly proportional to temperature
Answer: B) Inversely proportional to pressure
When you increase the pressure on a gas at constant temperature, its volume decreases. A bicycle pump demonstrates this law.
16. Charles’s law relates the volume of a gas to its:
A) Pressure
B) Mass
C) Absolute temperature
D) Density
Answer: C) Absolute temperature
At constant pressure, the volume of a gas increases as its absolute temperature (in Kelvin) increases.
17. What is the value of Avogadro’s number?
A) 6.022 × 10²³
B) 3.0 × 10⁸
C) 6.626 × 10⁻³⁴
D) 9.8 × 10²³
Answer: A) 6.022 × 10²³
One mole of any substance contains 6.022 × 10²³ particles. The other options are distractors: 3.0 × 10⁸ m/s is the speed of light and 6.626 × 10⁻³⁴ is Planck’s constant.
18. What is “dry ice”?
A) Frozen water
B) Solid carbon dioxide
C) Solid nitrogen
D) Frozen ammonia
Answer: B) Solid carbon dioxide
Dry ice changes directly from solid to gas without melting. Scientists call this process sublimation.
Acids, Bases and Salts MCQs
19. What is the pH of pure water at 25°C?
A) 0
B) 5
C) 7
D) 14
Answer: C) 7
Pure water is neutral at 25°C. A pH below 7 shows an acid, and a pH above 7 shows a base.
20. Which acid is present in vinegar?
A) Citric acid
B) Acetic acid
C) Lactic acid
D) Formic acid
Answer: B) Acetic acid
Vinegar is a dilute solution of acetic acid. Examiners frequently ask about natural acids, so learn this full set:
- Lemon: citric acid
- Sour milk: lactic acid
- Ant sting: formic acid
- Stomach: hydrochloric acid
- Vinegar: acetic acid
21. An acid turns blue litmus paper:
A) Green
B) Yellow
C) Red
D) Colourless
Answer: C) Red
Acids turn blue litmus red, while bases turn red litmus blue. The memory trick is simple: “Acid makes it red.”
22. The reaction between an acid and a base produces:
A) Salt and hydrogen
B) Salt and water
C) Water and oxygen
D) Only salt
Answer: B) Salt and water
This reaction is called neutralization. Antacid tablets use it to relieve excess stomach acid.
Common Compounds and Industrial Chemistry MCQs
23. What is the chemical formula of baking soda?
A) Na₂CO₃
B) NaHCO₃
C) NaCl
D) NaOH
Answer: B) NaHCO₃
Baking soda is sodium bicarbonate. Washing soda is sodium carbonate (Na₂CO₃·10H₂O). Candidates often confuse the two, so revise them together.
24. Laughing gas is the common name of:
A) Nitric oxide
B) Nitrous oxide
C) Nitrogen dioxide
D) Ammonia
Answer: B) Nitrous oxide
Nitrous oxide (N₂O) causes a mild euphoric effect when inhaled. Doctors and dentists use it as a mild anaesthetic.
25. Brass is an alloy of:
A) Copper and tin
B) Copper and zinc
C) Iron and carbon
D) Aluminium and copper
Answer: B) Copper and zinc
Brass contains copper and zinc. Bronze contains copper and tin, and steel is mainly iron with a small amount of carbon.
26. Galvanization coats iron with a layer of:
A) Tin
B) Copper
C) Zinc
D) Chromium
Answer: C) Zinc
The zinc layer protects iron from rusting. Even when the coating gets scratched, zinc corrodes first and shields the iron underneath.
27. Which catalyst does the Haber process use to make ammonia?
A) Platinum
B) Nickel
C) Iron
D) Vanadium pentoxide
Answer: C) Iron
The Haber process combines nitrogen and hydrogen over an iron catalyst. Vanadium pentoxide is the catalyst in the Contact process for sulphuric acid, which is a common distractor.
28. What is the hardest naturally occurring substance?
A) Graphite
B) Quartz
C) Diamond
D) Iron
Answer: C) Diamond
Each carbon atom in diamond bonds strongly to four other carbon atoms in a rigid 3D network. Graphite is also pure carbon, but its layered structure makes it soft.
29. Which metal is present in chlorophyll?
A) Iron
B) Magnesium
C) Copper
D) Zinc
Answer: B) Magnesium
Chlorophyll contains magnesium, while haemoglobin contains iron. This pair appears often in both Chemistry and Everyday Science papers.
30. What is heavy water?
A) H₂O₂
B) D₂O
C) H₂O with salt
D) Frozen water
Answer: B) D₂O
Heavy water contains deuterium, an isotope of hydrogen, in place of ordinary hydrogen. Nuclear reactors use it as a moderator.
Organic Chemistry MCQs
31. What is the general formula of alkanes?
A) CₙH₂ₙ
B) CₙH₂ₙ₊₂
C) CₙH₂ₙ₋₂
D) CₙHₙ
Answer: B) CₙH₂ₙ₊₂
Alkanes contain only single bonds. Alkenes follow CₙH₂ₙ and alkynes follow CₙH₂ₙ₋₂.
32. What is the main component of natural gas?
A) Ethane
B) Propane
C) Methane
D) Butane
Answer: C) Methane
Methane (CH₄) makes up most of natural gas, including the Sui gas used in Pakistani homes.
33. Compounds with the same molecular formula but different structures are called:
A) Isotopes
B) Isomers
C) Allotropes
D) Polymers
Answer: B) Isomers
Isomers share a formula but differ in how their atoms are arranged. Butane and isobutane are a simple example. Don’t confuse isomers (compounds) with isotopes (atoms).
34. What is the molecular formula of benzene?
A) C₆H₁₂
B) C₆H₆
C) C₆H₁₄
D) C₅H₁₀
Answer: B) C₆H₆
Benzene is a ring of six carbon atoms with alternating double bonds. Its structure makes it the parent compound of aromatic chemistry.
35. Oxidation is defined as the:
A) Gain of electrons
B) Loss of electrons
C) Gain of hydrogen
D) Loss of oxygen
Answer: B) Loss of electrons
Use the memory trick “OIL RIG”: Oxidation Is Loss, Reduction Is Gain of electrons.
How to Prepare Chemistry MCQs Effectively
Study concepts, not wording. Examiners change the wording of a question but keep the concept. When you understand why ice floats, you can answer any question about hydrogen bonding or density.
Learn facts in pairs. Chemistry papers love pairs that look similar:
- Brass and bronze
- Baking soda and washing soda
- Isotopes and isomers
- Mercury and bromine
- Chlorophyll and haemoglobin
When you revise one fact, revise its partner too.
Practice in timed sets. Solve 20 to 25 MCQs at a time and give yourself about 30 seconds per question. This builds the speed you need in the exam hall. Our guide on solving PPSC and FPSC MCQs faster explains this method in detail.
Keep a mistake log. Write down every question you get wrong, along with the correct reason. Review this log in the final week before your test.
Revise with spaced repetition. Return to each topic after three days, then again after a week. Short, repeated revision fixes facts in long-term memory far better than one long session.
Common Mistakes Candidates Make
- Mixing up atomic number and mass number. Atomic number counts protons only; mass number counts protons plus neutrons.
- Confusing Mendeleev’s law with the modern periodic law. Mendeleev used atomic mass, but the modern table uses atomic number.
- Swapping the most abundant element with the most abundant metal. Oxygen is the most abundant element in the Earth’s crust, while aluminium is the most abundant metal.
- Ignoring Everyday Science chemistry. Many candidates skip common chemicals and household compounds, even though one-paper tests ask about them regularly.
Frequently Asked Questions
Which topics carry the most Chemistry MCQs in PPSC tests?
Atomic structure, the periodic table, acids and bases, and common compounds appear in most papers. Lecturer-level tests add physical and organic Chemistry in more depth.
Are Chemistry MCQs part of the PPSC one-paper test?
Yes, they usually appear within the Everyday Science or General Science section. These questions focus on practical, everyday Chemistry rather than advanced theory.
How many Chemistry MCQs should I practice daily?
Aim for 25 to 50 questions a day, divided into short timed sets. Consistent daily practice works better than long, irregular sessions.
What is the best way to remember chemical formulas?
Group formulas by type, such as acids, salts and gases, and revise similar formulas together. Writing them down from memory once a day also improves recall.
Where can I practice more Chemistry MCQs online for free?
You can practice topic-wise Chemistry MCQs with answers on the MCQsDrive Chemistry section. The site also offers a quiz mode that lets you test yourself under time limits.
Conclusion
Chemistry rewards candidates who understand concepts instead of memorizing lines. Focus first on the high-frequency topics: atomic structure, the periodic table, bonding, acids and bases, and common compounds. Then practice in timed sets, learn confusing facts in pairs, and review your mistakes regularly.
Ready to test yourself? Visit the MCQsDrive Chemistry MCQs page for more solved questions. You can also strengthen your science preparation with our Physics MCQs with Answers, Biology MCQs for PPSC, FPSC & NTS and Everyday Science MCQs Guide.
