Free Chemistry in Daily Life MCQs with Answers

71. Which of the following is liquid fuel ?

• A. Patrol
• B. Kerosene
• C. Paraffin oil
• D. All of above

Explanation: Petrol, kerosene, and paraffin oil are all liquid fuels at ordinary temperatures. The word “patrol” is evidently a typo for “petrol.”

72. The position of an element in the Periodic Table is determined by its __________ number?

• A. Electron
• B. Proton
• C. Neutron
• D. None of these

Explanation: An element’s position in the modern periodic table is determined by its atomic number, which equals the number of protons in its nucleus. Electron and neutron numbers can vary among isotopes or ions.

73. Proteins are made up of _________?

• A. Polynucleotide
• B. Polypeptide
• C. Oxyacetylene
• D. None of these

Explanation: Proteins are polymers made from amino acids joined by peptide bonds, forming one or more polypeptide chains. Polynucleotides are the polymer chains of DNA and RNA, not proteins.

74. Permanent hardness of water is due to the presence of __________?

• A. Sodium bicarbonate
• B. Calcium sulfate
• C. Calcium bicarbonate
• D. None of these

Explanation: Permanent hardness is caused mainly by soluble calcium or magnesium sulfates and chlorides; calcium sulfate is one listed example. Calcium bicarbonate causes temporary hardness and can be removed by boiling.

75. Water present in watermelon?

• A. 92%
• B. 93%
• C. 94%
• D. 95%Standardized & Admissions Tests

Explanation: Water makes up about 92% of a watermelon’s mass, which explains its juicy texture and low calorie density. The exact value varies somewhat with variety and ripeness.

76. How many elements are in modern periodic table?

• A. 118
• B. 181
• C. 108
• D. 188Preparing For College Admissions Tests

Explanation: The modern periodic table contains 118 officially recognized elements, ending with oganesson at atomic number 118. The other figures do not represent the current total.

77. Which is the most electro-negative element among the following _________?

• A. Fluorine
• B. Bromine
• C. Sodium
• D. Oxygen

Explanation: Fluorine is the most electronegative element because its small atomic size and strong effective nuclear attraction give it the greatest tendency to attract bonding electrons. Oxygen and bromine are also electronegative, but less so.

78. The metal that is used as a catalyst in the hydrogenation of oils is _______?

• A. Ni
• B. Pb
• C. Cu
• D. Pt

Explanation: Nickel catalyses the hydrogenation of vegetable oils, adding hydrogen to unsaturated bonds and making the oil more saturated. Lead, copper, and platinum are not the usual industrial catalyst for this process.

79. 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.

80. 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.