Chemistry in Daily Life MCQs – Page 2

Solved Everyday Science MCQs on chemical symbols, common compounds and formulas, acids and bases, metals and gases used in daily life.

1. 21

   Which of the following is a noble (inert) gas?

   ANitrogenBNeonCChlorineDFluorine

   Correct answer: B. Neon

   Neon belongs to group 18, the noble gases, whose full outer electron shells make them very unreactive.

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2. 22

   Temporary hardness of water is caused by dissolved:

   ASodium chlorideBCalcium and magnesium bicarbonatesCIron oxideDPotassium nitrate

   Correct answer: B. Calcium and magnesium bicarbonates

   Calcium and magnesium bicarbonates cause temporary hardness, which boiling removes. Their sulphates and chlorides cause permanent hardness.

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3. 23

   The chemical formula of common washing soda is:

   ANaOHBNaHCO₃CNa₂CO₃·10H₂ODCaCO₃

   Correct answer: C. Na₂CO₃·10H₂O

   Washing soda is hydrated sodium carbonate (Na₂CO₃·10H₂O), used to soften water and for cleaning.

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4. 24

   Marble and limestone are mainly composed of:

   ASilicon dioxideBCalcium carbonateCSodium carbonateDCalcium sulphate

   Correct answer: B. Calcium carbonate

   Both are mainly calcium carbonate (CaCO₃). Marble is limestone that has been changed by heat and pressure.

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5. 25

   Which gas is mainly responsible for the greenhouse effect caused by burning fossil fuels?

   ACarbon dioxideBArgonCNitrogenDOxygen

   Correct answer: A. Carbon dioxide

   Burning coal, oil and gas releases carbon dioxide, which traps heat in the atmosphere and drives global warming.

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