Change in pH: practical
I can investigate the change in pH on adding base to a fixed volume of acid.
Change in pH: practical
I can investigate the change in pH on adding base to a fixed volume of acid.
Lesson details
Key learning points
- When powdered hydroxide/oxide (base) is added to an acidic solution there is an increase in pH.
- pH changes quickly around the neutralisation point.
- Indicators, such as Universal Indicator paper, can be used to collect quantitative data on pH.
- pH can be plotted on a graph to find the quantity of base required to neutralise an acid.
Common misconception
All added calcium hydroxide dissolves completely, and the pH readings are accurate without consistent mixing.
Calcium hydroxide has low solubility in water, so not all of it dissolves readily. Consistent mixing ensures uniform pH readings. Without proper mixing, pH readings can be inaccurate, leading to incorrect conclusions about the neutralisation point.
Keywords
PH - A measure of the hydrogen ion (H⁺) concentration in a solution.
Neutralisation - A chemical reaction between an acid and base to produce a neutral solution of a metal salt and water.
Base - A substance that neutralises an acid to form a salt and water.
Quantitative - Refers to a measurement of quantity. A numerical value.
Equipment
UI paper, white tiles, dilute HCl, measuring cylinders, beakers, glass rods, top-pan balance, weighing boats, spatulas, calcium hydroxide powder, graph paper, rulers, UI pH scales.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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Starter quiz
6 Questions
Exit quiz
6 Questions
a measure of hydrogen ion concentration
a reaction between an acid and a base
increases pH when added to an acid
data represented as numerical values
responsible for acidity in a solution