- No data uploaded
- Instant results
RRB JE Chemistry Questions
Practise chemistry (science) for the RRB Junior Engineer Examination: 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.The atomic number of an element equals the number of:
Show answer & explanation
Answer: D — Protons
Atomic number = number of protons in the nucleus.
-
Q2.What is the mass of 2 mol of water (H₂O)? (Molar mass 18 g/mol)
Show answer & explanation
Answer: C — 36 g
Mass = moles × molar mass = 2 × 18 g/mol = 36 g.
-
Q3.The process of converting a solid directly into a gas is called:
Show answer & explanation
Answer: B — Sublimation
Sublimation, e.g. dry ice or naphthalene.
-
Q4.What is the pH of a solution with [H⁺] = 10⁻³ mol/L?
Show answer & explanation
Answer: D — 3
pH = −log[H⁺] = −log(10⁻³) = 3.
-
Q5.The noble gas used in advertising signs that glows red-orange is:
Show answer & explanation
Answer: B — Neon
Neon glows red-orange in discharge tubes.
-
Q6.What is the pH of a solution with [OH⁻] = 10⁻⁶ mol/L at 25 °C?
Show answer & explanation
Answer: A — 8
[OH⁻] = 10⁻⁶ → pOH = 6; pH = 14 − 6 = 8 (at 25 °C).
-
Q7.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.
-
Q8.What is the mass of 4 mol of water (H₂O)? (Molar mass 18 g/mol)
Show answer & explanation
Answer: A — 72 g
Mass = moles × molar mass = 4 × 18 g/mol = 72 g.
-
Q9.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.
-
Q10.What is the pH of a solution with [H⁺] = 10⁻¹ mol/L?
Show answer & explanation
Answer: B — 1
pH = −log[H⁺] = −log(10⁻¹) = 1.
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 RRB JE
RRB Junior Engineer Examination — conducted by Railway Recruitment Boards (RRB). Recruits Junior Engineers, Depot Material Superintendents and Chemical & Metallurgical Assistants.
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.
RRB JE practice topics
| Topic | Section | Question source |
|---|---|---|
| Physics | Science | Calculated + question bank |
| Chemistry | Science | Calculated + question bank |
| Number System & Simplification | Quantitative aptitude | Calculated (new numbers every set) |
| Logical Reasoning | Reasoning | Calculated (new numbers every set) |
| Computer Awareness | Computer knowledge | Question bank |