These 9th class chemistry chapter 10 notes are ExamPaperDesk’s own solved answers to the Chapter 10 exercise, Environmental Chemistry, in both English medium and Urdu medium. Each PDF covers the chapter’s short-answer questions and constructed response questions, with clear answers you can revise from and follow when writing your own. Choose the English medium PDF (2 pages) or the Urdu medium PDF (2 pages) below.
After revising the answers, test yourself with the Class 9 Chemistry test papers. The Class 9 Chemistry section of ExamPaperDesk brings notes, test papers, online papers, guess papers and past papers together, and you can browse all Class 9 Chemistry notes here.
Chapter 10 Notes English Medium PDF
Chapter 10 Notes Urdu Medium PDF
Chapter 10 Exercise: What You Are Expected to Be Able to Write
These solved answers cover the Chapter 10 exercise, Environmental Chemistry. Reading a model answer is useful only as a check. The point of the exercise is that you can produce these yourself, in writing, under exam conditions. The chapter expects you to handle:
- The composition and layers of the atmosphere.
- Major air pollutants, their sources, and their effects on health and the environment.
- Acid rain, its formation from oxides of sulphur and nitrogen, and its consequences.
- The greenhouse effect, global warming and ozone depletion.
- Water pollution, its sources and its effects.
- Water treatment, and the difference between soft and hard water.
The Statements That Must Be Exact
Chemistry is marked on precision of wording more than on length. For Environmental Chemistry, these must be right:
- Acid rain forms when oxides of sulphur and nitrogen dissolve in atmospheric water to give sulphuric and nitric acids.
- The greenhouse effect is caused mainly by carbon dioxide, methane and water vapour trapping outgoing infrared radiation.
- Hard water contains dissolved calcium and magnesium salts, which is why it forms scum with soap.
Errors That Appear Year After Year
- Confusing the greenhouse effect with ozone depletion; they have different causes.
- Naming carbon dioxide as the cause of acid rain.
- Saying hard water is unsafe to drink, when the issue is scum and scale.
How to Use Solved Answers Without Wasting Them
Attempt the question first with the solution covered, then uncover it and compare line by line. Mark the difference, not just the verdict: a missing condition, a wrong sign or a vague phrase is the thing to carry forward. Copying a model answer out neatly feels productive and teaches almost nothing, because recognition is not recall.
Frequently Asked Questions
What causes acid rain?
Oxides of sulphur and nitrogen, released mainly by burning fossil fuels, dissolving in atmospheric moisture to form sulphuric and nitric acids, which then fall as rain.
Are both mediums available?
The solved answers cover the chapter exercise and are free to download and print, with no sign-up needed.
Related Class 9 Chemistry Resources
Once you can write the answers unaided, sit the Chapter 10 test paper, a 36-mark bilingual practice paper with an MCQ answer key. Everything else for the subject is on the Class 9 Chemistry page, with the rest of the solved exercises under Class 9 Chemistry notes.