Free Chemistry in Daily Life MCQs with Answers

21. Yeast is used in making bread because it produces____________?

• A. Carbon dioxide
• B. Sugar
• C. Bacteria
• D. Oxygen
• E. None of these

Explanation: Yeast ferments sugars in dough and releases carbon dioxide gas. The trapped gas bubbles make the dough rise, while the alcohol produced largely evaporates during baking.

22. Which one of the following is a non-metallic mineral?

• A. Manganese
• B. Magnesium
• C. Gypsum
• D. Bauxite
• E. None of these

Explanation: Gypsum is hydrated calcium sulfate, a non-metallic mineral used in plaster and cement. Manganese, magnesium and aluminium-bearing bauxite are classified as metallic mineral resources.

23. Diamond is a very expensive ornament. It is composed of a single element ___________?

• A. Carbon
• B. Gold
• C. Silver
• D. Platinum
• E. None of these

Explanation: Diamond is a crystalline allotrope of carbon, with each carbon atom bonded in a strong three-dimensional structure. Gold, silver and platinum are separate elements and are not diamond's composition.

24. Bronze is an alloy of ____________?

• A. Copper and Zinc
• B. Tin and Zinc
• C. Copper and Tin
• D. Iron and Zinc
• E. None of these

Explanation: Bronze is primarily an alloy of copper and tin. Copper and zinc form brass, which is the common alloy confused with bronze.

25. Chemical name of vinegar is _____________?

• A. Sodium Nitrate
• B. Dilute acetic acid
• C. Chloride of lime
• D. Calcium

Explanation: Vinegar is a dilute aqueous solution of acetic acid, usually containing about 4 to 8 percent acetic acid. The other options are unrelated chemicals or an incomplete name.

26. Dry ice is ___________?

• A. Methane hydrate
• B. Liquid Nitrogen
• C. Solid Carbon dioxide
• D. Frozen Water
• E. None of these

Explanation: Dry ice is solid carbon dioxide. It changes directly from solid to gas by sublimation, rather than melting into a liquid under ordinary atmospheric conditions.

27. Chemical used to kill rats and mice are ?

• A. Insecticides
• B. Rodenticides
• C. Fungicides
• D. Herbicides
• E. None of these

Explanation: Rodenticides are chemicals designed to kill rodents such as rats and mice. Insecticides target insects, fungicides target fungi and herbicides target weeds.

28. Role of biotechnology in the production of food based on ___________?

• A. Decomposition
• B. Respiration
• C. Digestion
• D. Fermentation
• E. None of these

Explanation: Fermentation uses microorganisms to convert sugars into useful products such as bread, yogurt, alcohol and organic acids. It is a controlled biochemical process, not ordinary digestion or decomposition.

29. Laughing gas has chemical composition of following two elements ?

• A. Nitrogen + Hydrogen
• B. Nitrogen + Carbon
• C. Nitrogen + Oxygen
• D. Oxygen + Carbon
• E. None of these

Explanation: Laughing gas is nitrous oxide, N₂O, so it contains nitrogen and oxygen. Its name refers to its temporary euphoric effects when inhaled, not to its chemical composition.

30. Which woody raw material is used for the manufacture of paper pulp?

• A. Cotton
• B. Poplar
• C. Bagasse
• D. Rice straw

Explanation: Poplar is a woody tree whose wood is processed into pulp for papermaking. Cotton, bagasse and rice straw are fibrous non-woody raw materials rather than woody material.