Free Chemistry in Daily Life MCQs with Answers

121. Of the six noble gases in the periodic table, which is the lightest?

• A. Nitrogen
• B. Hydrogen
• C. Helium
• D. Oxygen

Explanation: Helium is the lightest noble gas, with atomic number 2 and atomic mass about 4. Nitrogen, hydrogen and oxygen are not noble gases.

122. In onion pink color is due_____ ?

• A. anthocyanin
• B. Carotene
• C. Xanthophylls
• D. None of these

Explanation: Anthocyanin pigments produce red, purple, and pink colours in many plant tissues, including some onion varieties. Carotene and xanthophylls mainly produce yellow or orange colours.

123. Red color of tomato is due to___________?

• A. Anthocyanin
• B. Xanthophyll's
• C. Lycopene
• D. None of these

Explanation: Lycopene is the red carotenoid pigment that gives ripe tomatoes their characteristic colour. Anthocyanins commonly produce red-purple shades, while xanthophylls are yellow pigments.

124. Water has high density and minimum volume at__________?

• A. 0°C
• B. 4°C
• C. 100°C
• D. None of these

Explanation: Water reaches its maximum density and therefore minimum volume at 4°C under ordinary atmospheric pressure. Below 4°C it expands as it approaches freezing, an unusual property that helps ice float.

125. What is the nature of pH of Milk?

• A. Slightly Acidic
• B. Slightly Basic
• C. Highly Acidic
• D. Highly Basic

Explanation: Milk is slightly acidic, normally having a pH of about 6.5 to 6.7 rather than the neutral value of 7. It is not highly acidic because its weak acidity comes mainly from lactic acid and other natural constituents.

126. Liquids which evaporate quickly are known as___________?

• A. Evaporation
• B. Volatile
• C. Condense
• D. None

Explanation: Liquids that evaporate readily at ordinary temperatures are called volatile liquids because their particles escape easily from the surface. Evaporation is the process itself, not the name for the liquid.

127. In the manufacture of Vanaspati Ghee/Banaspati Ghee which gas is used ?

• A. Hydrogen
• B. Oxygen
• C. Nitrogen
• D. Carbon dioxide

Explanation: Hydrogen is added to vegetable oils during hydrogenation, converting some unsaturated fats into the semi-solid fat used in vanaspati ghee. Oxygen would promote oxidation rather than harden the oil in this process.

128. When sugar is added to water, its boiling point:__________?

• A. Increase
• B. Decrease
• C. Remain unchanged
• D. None of the above

Explanation: Dissolved sugar raises water's boiling point through boiling-point elevation, a colligative property of solutions. The increase is small for ordinary amounts of sugar but is still in the upward direction.

129. For glavinizing of iron which of the following metals is used ?

• A. Aluminimum
• B. Copper
• C. Zinc
• D. Lead

Explanation: Galvanizing protects iron by coating it with zinc, which acts as a barrier and also corrodes preferentially if the coating is damaged. This sacrificial protection is why zinc is used rather than copper or lead.

130. Which of the following is the lightest substance?

• A. Uranium
• B. Hydrogen
• C. Oxygen
• D. Nitrogen

Explanation: Hydrogen has the lowest atomic and molecular mass of all elements, making it lighter than oxygen, nitrogen and uranium. In ordinary conditions, hydrogen exists as a very light gas.