Acids, bases and the pH scale
pH below 7 is acidic, 7 is neutral, above 7 is alkaline.
The common mistake
Thinking a higher pH means a stronger acid.
Instead: Lower pH = more acidic; each step down is 10× more H⁺ ions. Acid + base → salt + water.
Worked example with Guide me
Which is more acidic: pH 3 or pH 5? By how much?
- Sugar · Which number is lower?Student · 3.
- Sugar · How many steps apart?Student · 2, so 10 × 10.
Answer: pH 3 — 100 times more acidic.
Try 3 practice questions
1. pH of pure water?
Show answer
7
2. What ion do acids release in water?
Show answer
H⁺
3. Products of HCl + NaOH?
Show answer
NaCl + H₂O
Quick answers
- What is the most common mistake with acids, bases and the ph scale?
- Thinking a higher pH means a stronger acid.
- How do I get acids, bases and the ph scale right?
- Lower pH = more acidic; each step down is 10× more H⁺ ions. Acid + base → salt + water.
- Can you show a worked example?
- Which is more acidic: pH 3 or pH 5? By how much? pH 3 — 100 times more acidic.
Related concepts
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