All Free Everyday Science MCQs with Answers

371. Caustic Soda is extensively used for making __________?

• A. Surf
• B. Soap
• C. Plaster of Paris
• D. Gum

Explanation: Caustic soda, or sodium hydroxide, reacts with fats and oils in saponification to make soap. Plaster of Paris is made from gypsum, not sodium hydroxide.

372. Enzymes are organic catalysts made up of __________?

• A. Carbohydrates
• B. Proteins
• C. Nucleic Acid
• D. Fats

Explanation: Most enzymes are proteins folded into shapes that provide active sites for chemical reactions, allowing them to act as biological catalysts. A small number of catalytic RNA molecules exist, but the standard answer is proteins.

373. Plant have ________ while animals lack it.

• A. starch
• B. cellulose
• C. protein
• D. fat

Explanation: Plant cell walls contain cellulose, a structural polysaccharide that animals generally cannot digest or produce as a cell-wall material. Plants also contain starch, proteins and fats, so cellulose is the distinguishing option here.

374. Gold and Silver are known as _________ metals ?

• A. Coinage metals
• B. Noble metals
• C. Both A & B
• D. None of these

Explanation: Gold and silver are noble metals because they resist oxidation and corrosion, and both have historically been used to make coins. Thus they fit both the noble-metal and coinage-metal categories.

375. An important ore of chromium is ___________?

• A. Argon
• B. Chromite
• C. Mirage
• D. Diamond

Explanation: Chromite, chiefly an iron chromium oxide, is the principal commercial ore of chromium. Argon is a noble gas, while mirage is an optical phenomenon and diamond is carbon.

376. Another name of RDX is ___________?

• A. Cyanohydrin
• B. Dextran
• C. Cyclohexane
• D. Cyclonite

Explanation: RDX is also called cyclonite, a powerful cyclic nitramine explosive. The other names do not refer to RDX or to an equivalent chemical compound.

377. Garnet is a______________?

• A. Sedimentary rock
• B. Igneous rock
• C. Mineral
• D. None of these

Explanation: Garnet is a group of crystalline minerals, commonly used as a gemstone and as an abrasive. It is not classified as a sedimentary or igneous rock.

378. Which metal known as quick silver ?

• A. Mercury
• B. Sulphuric acid
• C. Chromite
• D. Quartz

Explanation: Mercury is called quicksilver because it is a silvery liquid metal that flows rapidly at room temperature. The other options are compounds or minerals, not metals.

379. Which one of the following is a bio molecule?

• A. Formic Acid
• B. Tartic Acid
• C. Glutamic Acid
• D. Glutaric Acid

Explanation: Glutamic acid is an amino acid used in proteins, making it a clear biomolecule. The other substances are organic acids but are not standard examples of biological molecules in this context.

380. What makes a lemon sour?

• A. Tartaric Acid
• B. Citric Acid
• C. Acetic Acid
• D. Hydrochloric Acid

Explanation: Citric acid gives lemons their characteristic sour taste and is also present in other citrus fruits. Tartaric acid is associated mainly with tamarind and grapes, while acetic acid is found in vinegar.