Which one of the following statements is NOT correct?

4 gram of hydrogen gas contains 6·022 × 10²³ molecules

Half mole of nitrogen gas is measured 11·2 litre at STP

17 gram of ammonia gas contains 6·022 × 10²³ molecules at STP

22·4 litre of CO₂ gas at STP contains 44 gram of CO₂

Chemistry — NDA Previous Year Questions

137 solved PYQs · 2021–2025 · General Science

Solved PYQs: 137
Years covered: 2021–2025
Avg / year: ~27
Subject: General Science

How many NDA questions come from Chemistry?

Chemistry has contributed 137 questions to National Defence Academy Examination papers between 2021 and 2025 — an average of about 27 questions a year. That count is measured from EByAi’s bank of 15,695 NDA questions, not estimated from a syllabus. Every one of the 137 questions carries a written, step-by-step solution, and each is tagged to Chemistry within General Science, so you can drill this chapter across every year at once instead of hunting through paper PDFs. Practising a chapter’s full PYQ history is the fastest way to learn the patterns examiners reuse.

Sample Chemistry questions from real NDA papers

These are 5 real questions from the bank — exactly as asked, with the answer one tap away. All 137 Chemistry questions (with full written solutions) are available in practice.

Question 1 · NDA 2025
Which one of the following is known as ‘water gas’ ?
1. (A) $H2O + CO2$
2. (B) $NH3$
3. (C) $H2 + N2$
4. (D) $CO + H2$
Show answerAnswer
$Answer: (D) CO + H2$
Question 2 · NDA 2025
Which one of the following is NOT present in cement?
1. (A) $2CaO.SiO2$
2. (B) $3CaO.SiO2$
3. (C) $4CaO.SiO2$
4. (D) $3CaO.Al2O3$
Show answerAnswer
$Answer: (C) 4CaO.SiO2$
Question 3 · NDA 2025
Which one of the following is NOT a chemical change ?
1. (A) $Burning of coal$
2. (B) $Rusting of metal$
3. (C) $Melting of ice$
4. (D) $Reaction of acid with base$
Show answerAnswer
$Answer: (C) Melting of ice$
Question 4 · NDA 2025
Which one of the following oxides is a neutral oxide?
1. (A) $CO$
2. (B) $CO₂$
3. (C) $Na₂O$
4. (D) $MgO$
Show answerAnswer
$Answer: (A) CO$
Question 5 · NDA 2025
Which one of the following statements is NOT correct?
1. (A) $Half mole of nitrogen gas is measured 11\cdot2 litre at STP$
2. (B) $17 gram of ammonia gas contains 6\cdot022 \times 10²³ molecules at STP$
3. (C) $22\cdot4 litre of CO₂ gas at STP contains 44 gram of CO₂$
4. (D) $4 gram of hydrogen gas contains 6\cdot022 \times 10²³ molecules$
Show answerAnswer
$Answer: (D) 4 gram of hydrogen gas contains 6\cdot022 \times 10²³ molecules$

Chemistry questions by year

Year	Questions	Share of chapter questions
2025	29
2024	30
2023	35
2022	28
2021	15

Practise these 137 questions with solutions

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FAQs

How many NDA questions have been asked from Chemistry?

EByAi's bank holds 137 real NDA questions from Chemistry, asked between 2021 and 2025 — about 27 per year on average. Every count is measured from actual papers, not estimated.

Is Chemistry important for NDA?

137 questions over 5 papers make Chemistry a moderate-weightage chapter in NDA General Science. The year-wise table above shows exactly how often it appears.

Can I solve Chemistry PYQs online for free?

Yes. EByAi lets you solve NDA past-year questions in the browser with written solutions — free daily practice, no card needed.

More NDA General Science chapters

All NDA General Science chapters →NDA overview →