All Free Everyday Science MCQs with Answers

431. The element common to all acids is:__________?

• A. Hydrogen
• B. Carbon
• C. Sulphur
• D. Oxygen

Explanation: Acids contain hydrogen and produce hydrogen ions, or hydronium ions in water, which account for their acidic properties. Carbon, sulphur, and oxygen occur in some acids but not in all acids.

432. Aviation fuel for Jet Aeroplanes consists of purified________?

• A. Petrol
• B. Kerosene
• C. Gasoline
• D. Diesel

Explanation: Jet fuel is a purified kerosene fraction obtained from petroleum and is suitable for turbine engines. Petrol and gasoline are mainly used in spark-ignition engines, while diesel is a heavier fuel.

433. The natural source of hydrocarbon is:___________?

• A. Crude oil
• B. Biomass
• C. Coal
• D. Carbohydrates

Explanation: Crude oil is a naturally occurring mixture rich in hydrocarbons, including alkanes and aromatic compounds. It is refined into fuels and many petrochemical products.

434. The main Constituent of Biogas is__________?

• A. Methane
• B. Hydrogyn
• C. Oxygen
• D. Carbin dioxide

Explanation: Biogas is produced by anaerobic decomposition of organic matter and consists mainly of methane, with carbon dioxide and traces of other gases. Methane is the part that makes biogas combustible.

435. In whole Periodic Table which element Is Most Reducing Agent ?

• A. Chlorine
• B. lithium
• C. Helium
• D. Neon

Explanation: Lithium is a powerful reducing agent because it readily loses its outer electron and has a very negative standard reduction potential. Chlorine is instead a strong oxidizing agent, while helium and neon are largely inert.

436. Example of gas having monoatomic molecules is ___________ ?

• A. Nitrogen
• B. Nydrogen
• C. Neon and argon
• D. Oxygen and nitrogen

Explanation: Neon and argon are noble gases that exist as single atoms, so their molecules are described as monatomic. Nitrogen and oxygen normally occur as diatomic molecules, N₂ and O₂.

437. Atom was a name given by ____________ ?

• A. Democritus
• B. Bohr
• C. Rutherford
• D. Archimedes

Explanation: Democritus used the word atomos, meaning indivisible, for the smallest proposed particles of matter. Bohr and Rutherford later developed models of the atom rather than naming it.

438. How many Calories are there in 100 grams Natural Honey?

• A. 107
• B. 209
• C. 304
• D. 416

Explanation: Natural honey provides about 304 kilocalories per 100 grams, mainly from its sugars such as fructose and glucose. Its exact value varies slightly with water content and composition.

439. What is chemical symbol for Tungsten?

• A. Z
• B. T
• C. Tn
• D. W

Explanation: Tungsten has the symbol W, derived from its older name wolfram. Its English name does not begin with W, which makes the symbol a common recall question.

440. Which of the following are the ingredients of gun metal?

• A. Iron, Zinc and Titanium
• B. Iron and Tin
• C. Iron, Brass and Tin
• D. Copper, Tin and Zinc

Explanation: Gunmetal is a copper alloy containing tin and zinc, commonly approximated as about 88% copper, 10% tin, and 2% zinc. Iron-based alloys are not gunmetal.