Questions (120)
Q1CDS2018
Two reactants in a flask at room temperature are producing bubbles of a gas that turn limewater milky. The reactants could be
- A zinc and hydrochloric acid
- B magnesium carbonate and hydrochloric acid ✓
- C methane and oxygen
- D copper and dilute hydrochloric acid
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
Q2CDS2018
How many moles of CO can be obtained by reacting 2.0 mole of CH4 with 2.0 mole of O2 according to the equation given below? CH4(g) + 1/2 O2 -> CO + 2H2
- A 2.0 ✓
- B 0.5
- C 2.5
- D 4.0
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
Q3CDS2018
Reaction between which of the following two reactants will produce hydrogen gas?
- A Magnesium and hydrochloric acid ✓
- B Copper and dilute nitric acid
- C Calcium carbonate and hydrochloric acid
- D Zinc and nitric acid
✓ Correct answer: (A)
Science & Technology › Physics & Chemistry
Study how UPSC repeats — not just the papers
₹199 / 1 year · Founding Member
Full access unlocks the three things no PYQ PDF gives you:
① Cross-exam learning — see the same idea recur across CSE, CAPF, CDS and NDA.
② Topic evolution — how each idea is framed, year by year.
③ Question intelligence — every PYQ + answer, linked to related concepts and similar questions.
e.g. Round Table Conference: CDS 2017 → CSE 2017 → … → CAPF 2024
15 days free, no card required — then ₹199 for 1 year.
Start your 15-day free trial →