Free Chemistry in Daily Life MCQs with Answers

31. Rectified spirit contains alcohol about ?

• A. 80%
• B. 95%
• C. 70%
• D. 85%Exploring Online Chemistry Courses

Explanation: Rectified spirit is highly purified ethanol obtained by repeated distillation and typically contains about 95% alcohol by volume. It is not completely pure because ethanol and water form an azeotropic mixture.

32. Bronze medal is made up of metals ?

• A. copper,nickel
• B. copper, tin
• C. copper, silver
• D. copper, zinc

Explanation: Bronze is traditionally an alloy of copper and tin, valued for its hardness and corrosion resistance. Copper and zinc form brass, which is the common alternative trap.

33. The three elements needed for healthy growth of plants are __________?

• A. N, P, K
• B. N, C, P
• C. N, K,
• D. N, S, P

Explanation: Nitrogen, phosphorus and potassium are the three primary macronutrients required by plants. They support leafy growth, roots and reproduction, and overall water and enzyme regulation respectively.

34. The fourth state of matter is?

• A. Water
• B. Salts
• C. Vapours
• D. Plasma

Explanation: Plasma is an ionised gas containing free electrons and ions, and it behaves differently from solids, liquids and ordinary gases. Lightning, neon signs and stars contain plasma.

35. The natural fats and oils are composed of_________?

• A. Carbon, Hydrogen and Oxygen
• B. Carbon, Hydrogen and Nitrogen
• C. Carbon, Oxygen and Nitrogen
• D. Hydrogen, Oxygen and Nitrogen

Explanation: Natural fats and oils are mainly triglycerides, whose molecules contain carbon, hydrogen and oxygen. Nitrogen is not a basic element of ordinary triglycerides.

36. The gas, commonly known as "laughing gas", is

• A. Carbon Dioxide
• B. Sulfur Dioxide
• C. Nitrous Oxide
• D. Sodium Oxide

Explanation: Nitrous oxide, N2O, is called laughing gas and has been used as an inhaled anaesthetic and analgesic. It is different from nitrogen dioxide, a toxic brown atmospheric pollutant.

37. Diamond is an allotropic form of_______?

• A. Carbon
• B. Hydrogen
• C. Nitrogen
• D. Silicon

Explanation: Diamond is an allotrope of carbon, meaning it is a different structural form of the same element. Graphite and graphene are other well-known carbon allotropes.

38. What is Dry Ice?

• A. Solid Oxygen
• B. Solid Carbon Dioxide
• C. Solid Hydrogen
• D. Solid Nitrogen

Explanation: Dry ice is carbon dioxide in its solid state. It changes directly into gas by sublimation instead of melting into a liquid at normal pressure.

39. Oxidation is a chemical reaction involving the __________?

• A. Gain of Electrons
• B. Loss of Electrons
• C. Gain of Protons
• D. Loss of Protons

Explanation: In modern redox terminology, oxidation means loss of electrons, while reduction means gain of electrons. The mnemonic OIL, Oxidation Is Loss, helps distinguish the two.

40. In a very low temperature which from the following will freeze at last?

• A. River water
• B. Canal water
• C. Sea water
• D. Water in a lake

Explanation: Sea water freezes last because dissolved salts lower its freezing point below that of fresh water. River, canal and lake water generally contain much less dissolved salt.