- No data uploaded
- Instant results
JEE Main Chemistry Questions
Practise chemistry (science) for the Joint Entrance Examination (Main): 10 multiple-choice questions, each with the correct answer and a worked explanation. Click an option to check it, or “New questions” for another set.
Chemistry practice
-
Q1.Which gas is responsible for most of the greenhouse effect from human activity?
Show answer & explanation
Answer: D — Carbon dioxide
CO₂ from burning fossil fuels is the largest human-caused contributor.
-
Q2.What is the pH of a solution with [OH⁻] = 10⁻¹ mol/L at 25 °C?
Show answer & explanation
Answer: C — 13
[OH⁻] = 10⁻¹ → pOH = 1; pH = 14 − 1 = 13 (at 25 °C).
-
Q3.Rusting of iron requires:
Show answer & explanation
Answer: A — Both oxygen and water
Iron rusts in the presence of oxygen and moisture, forming hydrated iron(III) oxide.
-
Q4.What is the pH of a solution with [H⁺] = 10⁻⁶ mol/L?
Show answer & explanation
Answer: D — 6
pH = −log[H⁺] = −log(10⁻⁶) = 6.
-
Q5.An oxidation reaction involves:
Show answer & explanation
Answer: A — Loss of electrons
Oxidation is loss of electrons (OIL RIG).
-
Q6.The hardest naturally occurring substance is:
Show answer & explanation
Answer: C — Diamond
Diamond, a carbon allotrope, is the hardest natural material.
-
Q7.What is the mass of 1 mol of carbon dioxide (CO₂)? (Molar mass 44 g/mol)
Show answer & explanation
Answer: A — 44 g
Mass = moles × molar mass = 1 × 44 g/mol = 44 g.
-
Q8.Water has a maximum density at about:
Show answer & explanation
Answer: D — 4 °C
Water is densest at about 4 °C.
-
Q9.58.5 g of NaCl (molar mass 58.5) is dissolved to make 1000 mL of solution. Find the molarity.
Show answer & explanation
Answer: A — 1 M
Moles = 58.5/58.5 = 1; molarity = moles ÷ litres = 1 ÷ 1 = 1 M.
-
Q10.Isotopes of an element have the same number of:
Show answer & explanation
Answer: A — Protons
Isotopes share the proton number but differ in neutrons.
How to approach chemistry questions
Moles = mass ÷ molar mass; molarity = moles ÷ litres. pH = −log[H⁺] and pH + pOH = 14 at 25 °C. For concepts, link each property to its position in the periodic table.
About JEE Main
Joint Entrance Examination (Main) — conducted by National Testing Agency (NTA). India’s national engineering entrance for NITs, IIITs and other institutes, and the qualifier for JEE Advanced.
Original practice questions written for this site in the style and difficulty of each exam’s syllabus. They are not past papers and the site is not affiliated with any exam body. Exam patterns, marking schemes and syllabi change — always check the latest official notification.
JEE Main practice topics
| Topic | Section | Question source |
|---|---|---|
| Algebra | Mathematics | Calculated (new numbers every set) |
| Geometry & Mensuration | Mathematics | Calculated (new numbers every set) |
| Probability & Combinatorics | Mathematics | Calculated (new numbers every set) |
| Physics | Science | Calculated + question bank |
| Chemistry | Science | Calculated + question bank |