Indicators

Question 1

What are indicators?

Answer 1

Substances that show whether a solution is acidic or alkaline by color change

Question 2

examples of indicators

Answer 2

Common natural indicator: litmus (red in acid, blue in base)

Synthetic indicators (e.g., methyl orange, phenolphthalein)

give sharper, faster color changes

Question 3

Why is litmus less suitable for titrations?

Answer 3

Its color change is gradual (red → purple → blue), making the endpoint hard to determine

Question 4

What is the pH scale?

Answer 4

Numerical scale 1–14
pH < 7: acidic, pH > 7: basic
Each decrease by 1 in pH → acidity increases 10×
Universal indicator shows approximate pH by color