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Environmental Chemistry MCQs for MDCAT Practice

Chemistry section, Environmental Chemistry chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 319 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    We used Pb(C2H5)4in the gasoline to reduce:
    • Consumption of fuel
    • Price of fuel
    • The octane number of fueL
    • Knocking of engine (correct answer)
    Correct answer: D
    Tetraethyllead (TEL), Pb(C2H5)4, was added to gasoline to prevent engine knocking by controlling combustion, not to affect fuel efficiency, price, or octane rating directly.
  2. Question 2
    The substance for the separation of isotopes is first converted into the:
    • Neutral state
    • Free state
    • Vapour state (correct answer)
    • Charged state
    Correct answer: C
    Separating isotopes relies on differences in their physical properties, necessitating conversion to a gaseous state for techniques like fractional distillation.
  3. Question 3
    Fluorosis, the bone disease, is caused by the presence of:
    • Pesticides in water
    • Fluorides in water (correct answer)
    • Carbon monoxide in air
    • Sulphur dioxide in air
    Correct answer: B
    Fluorosis, a skeletal disorder, arises from excessive fluoride intake, typically through contaminated water sources.
  4. Question 4
    The most abundant element in the earth crust is:
    • O (correct answer)
    • Si
    • Al
    • Fe
    Correct answer: A
    Oxygen is the most abundant element in Earth's crust, making up nearly half its mass, primarily in silicate minerals.
  5. Question 5
    Temporary hard water is softened on an industrial scale by adding
    • Mg(OH)2
    • Ca(OH)2 (correct answer)
    • KOH
    • NaOH
    Correct answer: B
    Industrial softening of temporary hard water relies on precipitating calcium and magnesium ions by adding a common base. This MCQ tests knowledge of water softening methods.
  6. Question 6
    Which of the following statement is not correct with respect to radioactive pollutants?
    • Carcinoma and breast cancer
    • Leukemia
    • Increases biological immune system (correct answer)
    • Somatic and genetic disorders
    Correct answer: C
    Radioactive pollutants are harmful, causing various cancers and disorders, not boosting the immune system.
  7. Question 7
    Which of the following causes water pollution?
    • Smoke/fly ash
    • Automobile exhausts
    • Aeroplanes
    • Silt and pesticides (correct answer)
    Correct answer: D
    This question differentiates between air pollutants and water pollutants, highlighting sources of contamination in aquatic ecosystems.
  8. Question 8
    Urban smog results in the formation of peroxyacetyl nitrate which causes damage to
    • rubber tyres.
    • kidney tissues.
    • the nervous system.
    • plant life. (correct answer)
    Correct answer: D
    Peroxyacetyl nitrate (PAN), a component of photochemical smog, primarily harms plant life by damaging leaf tissues and inhibiting photosynthesis.

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Read the full Environmental Chemistry chapter notes: Environmental Chemistry notes. Or browse every chapter.