Topic pH scale
Asked 5 times across 3 UPSC exams over 8 years (2017–2025), peaking in 2017.
Key insights
- Most tested in CDS — 2 of 5 PYQs
- Most asked in 2017
- Recurs across 5 years (2017–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CDS 2017 → NDA 2021 → GEO 2022
How the concept evolved
Rising — more than half its appearances (5 of 5) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
NDA2025
Which one of the following statements is NOT correct?
- A A scale measuring hydrogen ion concentration in a solution is called pH scale
- B The higher the hydrogen ion concentration in a solution, higher is its pH ✓
- C We can measure pH generally from 0 to 14 on a pH scale
- D The 'p' in pH stands for 'potenz' in German meaning power
✓ Correct answer: (B)
Science & Technology › Physics & Chemistry
CDS2023
Which one of the following is the correct order of pH for the given substances?
- A Coffee < Lemon juice < Milk of magnesia < Blood
- B Milk of magnesia < Blood < Coffee < Lemon juice
- C Lemon juice < Blood < Coffee < Milk of magnesia
- D Lemon juice < Coffee < Blood < Milk of magnesia ✓
✓ Correct answer: (D)
Science & Technology › Physics & Chemistry
GEO2022
As per the safe drinking water guidelines issued by the Bureau of Indian Standards, Government of India, what is the acceptable pH value of drinking water?
- A Between 7.5 and 9.5
- B Between 6.5 and 8.5 ✓
- C Between 5.5 and 7.5
- D Between 4.5 and 6.5
✓ Correct answer: (B)
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 →