ECAT Chemistry — Environmental Chemistry
Environmental Chemistry is part of the Chemistry section of the UET ECAT (30 of the 100 MCQs). It breaks into 2 subtopics, and we hold 10 ECAT-pattern practice MCQs on it, each with a written explanation. Tap a subtopic below to practise just that.
Subtopics (2)
How Environmental Chemistry is tested
Across the 7 ECAT past papers on ParhaiKrlo, Environmental Chemistry accounts for 3 questions. It appears in 3 of them, about 1 questions a paper. The heaviest was ECAT Past Paper 06, with 1 question.
| Paper | Questions |
|---|---|
| ECAT Past Paper 06 | 1 |
| ECAT Past Paper 04 | 1 |
| ECAT Past Paper 01 | 1 |
Environmental Chemistry MCQs from the ECAT past papers
Try each one before opening the answer. Each comes with a short explanation.
- Q1 · ECAT Past Paper 06 · Environmental Chemistry
The coagulant used in water treatment is:
- A.Gypsum
- B.Dolomite
- C.Asbestos
- D.Alum
Show answer
Answer: D. Alum — Alum produces Al³⁺, which forms a gelatinous Al(OH)₃ floc that traps suspended particles.
- Q2 · ECAT Past Paper 04 · Environmental Chemistry
Which of the following is NOT used to disinfect drinking water?
- A.Chlorine
- B.Ozone
- C.Calcium nitrate
- D.Chlorine dioxide
Show answer
Answer: C. Calcium nitrate — Chlorine, ozone and chlorine dioxide are oxidising disinfectants; calcium nitrate is a fertilizer.
- Q3 · ECAT Past Paper 01 · Environmental Chemistry
A single chlorine free radical can destroy about how many ozone molecules?
- A.100
- B.10000
- C.100000
- D.10
Show answer
Answer: C. 100000 — Cl• is regenerated in each cycle (Cl + O₃ → ClO + O₂; ClO + O → Cl + O₂), so one radical destroys about 10⁵ O₃ molecules.