Acids, Alkalis And Titrations
Overview
Every liquid you encounter, from lemon juice to bleach, sits somewhere on the pH scale. Knowing whether a substance is acidic, neutral, or alkaline is fundamental to chemistry, medicine, agriculture, and everyday life. Indicators give you a quick visual answer, while the pH scale puts a precise number on it.
In this lesson you will learn how to use litmus, phenolphthalein, and methyl orange to distinguish acids from alkalis, understand the pH scale from 0 to 14, use universal indicator to estimate pH, and discover why acids and alkalis behave the way they do at the ionic level. You will also see how neutralisation reactions work and why they always produce water.
Objectives
- Describe the use of litmus, phenolphthalein and methyl orange to distinguish between acidic and alkaline solutions
- Understand how to use the pH scale to classify solutions
- Describe the use of universal indicator to measure the approximate pH value of an aqueous solution
- Know that acids in aqueous solution are a source of hydrogen ions and alkalis are a source of hydroxide ions
- Know that alkalis can neutralise acids
Mind map
This topic is mapped out so you can see how the ideas connect.
Open the mind map in the app
Flashcards
Quick recall practice on the facts this topic is tested on.
Practise these cards in the app
Lesson Note
Complete Note Available on the Green Bridge App
Get the Green Bridge CBT app on your phone or computer for the complete IGCSE library: past papers, mark schemes, mind maps, flashcards and audio lessons.
Lesson Evaluation
Congratulations on completing the lesson on Acids, Alkalis And Titrations. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- What colour does phenolphthalein turn in an alkaline solution? A) Red B) Yellow C) Pink D) Colourless Answer: C
- A solution has a pH of 3. Which statement is correct? A) The solution is a strong alkali B) The solution is neutral C) The solution is acidic D) The solution is a weak alkali Answer: C
- Which ions are responsible for making a solution acidic? A) Sodium ions B) Hydroxide ions C) Hydrogen ions D) Chloride ions Answer: C
- Which indicator is most suitable for use in a titration? A) Litmus B) Universal indicator C) pH paper D) Phenolphthalein Answer: D
- What is the pH of a neutral solution? A) 0 B) 1 C) 7 D) 14 Answer: C
Work through these questions in the app
Work through these questions in the app
Practice Mock Questions
Want to practice mock questions on Acids, Alkalis And Titrations? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
Download The App On Google Playstore
Everything you need to excel in your exams
