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NDA Chemistry Questions
Practise chemistry (science) for the National Defence Academy & Naval Academy 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
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Q1.Which gas is responsible for most of the greenhouse effect from human activity?
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Answer: D — Carbon dioxide
CO₂ from burning fossil fuels is the largest human-caused contributor.
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Q2.What is the pH of a solution with [OH⁻] = 10⁻⁴ mol/L at 25 °C?
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Answer: A — 10
[OH⁻] = 10⁻⁴ → pOH = 4; pH = 14 − 4 = 10 (at 25 °C).
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Q3.Water has a maximum density at about:
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Answer: B — 4 °C
Water is densest at about 4 °C.
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Q4.What is the mass of 1.5 mol of carbon dioxide (CO₂)? (Molar mass 44 g/mol)
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Answer: C — 66 g
Mass = moles × molar mass = 1.5 × 44 g/mol = 66 g.
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Q5.The periodic table is arranged in order of increasing:
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Answer: C — Atomic number
The modern periodic table orders elements by atomic number.
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Q6.What is the pH of a solution with [OH⁻] = 10⁻² mol/L at 25 °C?
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Answer: B — 12
[OH⁻] = 10⁻² → pOH = 2; pH = 14 − 2 = 12 (at 25 °C).
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Q7.Rusting of iron requires:
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Answer: D — Both oxygen and water
Iron rusts in the presence of oxygen and moisture, forming hydrated iron(III) oxide.
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Q8.What is the mass of 2.5 mol of methane (CH₄)? (Molar mass 16 g/mol)
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Answer: C — 40 g
Mass = moles × molar mass = 2.5 × 16 g/mol = 40 g.
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Q9.Which bond is formed by the sharing of electrons?
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Answer: A — Covalent
Covalent bonds share electron pairs.
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Q10.What is the pH of a solution with [H⁺] = 10⁻⁵ mol/L?
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Answer: B — 5
pH = −log[H⁺] = −log(10⁻⁵) = 5.
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 NDA
National Defence Academy & Naval Academy Examination — conducted by Union Public Service Commission (UPSC). Entry to the tri-service National Defence Academy after Class 12, with Mathematics and General Ability papers.
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.
NDA practice topics
| Topic | Section | Question source |
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| 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 |
| English Grammar | English | Question bank |