Q1. What is the chemical symbol of water?
Correct: H2O
Water is composed of two hydrogen atoms and one oxygen atom.
Q2. Which gas is known as laughing gas?
Correct: Nitrous oxide
Nitrous oxide (N2O) is called laughing gas.
Q3. What is the atomic number of carbon?
Correct: 6
Carbon has 6 protons, so its atomic number is 6.
Q4. Which acid is present in vinegar?
Correct: Acetic acid
Vinegar contains acetic acid.
Q5. What is the pH value of pure water?
Correct: 7
Pure water is neutral with pH 7.
Q6. Which element is used in making thermometers?
Correct: Mercury
Mercury expands uniformly with temperature.
Q7. What is the chemical formula of common salt?
Correct: NaCl
Common salt is sodium chloride (NaCl).
Q8. Which gas is essential for combustion?
Correct: Oxygen
Oxygen supports combustion.
Q9. What is the hardest natural substance?
Correct: Diamond
Diamond is the hardest natural substance.
Q10. Which metal is liquid at room temperature?
Correct: Mercury
Mercury is liquid at room temperature.
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