Question 1

What is pH?

Accepted Answer

pH is a scale from 0 to 14 measuring acidity or alkalinity. pH 7 is neutral, below 7 is acidic, above 7 is alkaline.

Question 2

How does a pH meter work?

Accepted Answer

A pH meter measures the voltage between a glass electrode and reference electrode in a solution, converting it to a pH reading.

Question 3

What is a pH paper strip?

Accepted Answer

pH paper changes colour when dipped in a solution. Comparing the colour to a reference chart estimates the pH value.

Question 4

What is the pH of lemon juice?

Accepted Answer

Lemon juice has a pH of approximately 2–3, strongly acidic due to its high citric acid content.

Question 5

What liquids are acidic?

Accepted Answer

Acidic liquids include lemon juice (pH 2–3), vinegar (pH 2–3), orange juice (pH 3–4), coffee (pH 5–5.5), and carbonated drinks (pH 2.5–3.5).

Question 6

What liquids are alkaline?

Accepted Answer

Alkaline liquids include bleach (pH 12–13), ammonia solution (pH 11–12), baking soda solution (pH 8–9), and soap solution (pH 9–10).