SSC Stenographer 2026 PYQ — Question 32

Solution: The correct answer is H₂O.
Explanation:
☛ The chemical formula of water is H₂O, which signifies that each molecule of water is composed of two hydrogen atoms and one oxygen atom.
☛ The atoms in a water molecule are held together by polar covalent bonds.
☛ Water is widely known as the universal solvent because it can dissolve more substances than any other liquid.
Extra Exam-Relevant Facts:
☛ CO₂: Chemical formula for Carbon Dioxide, a major greenhouse gas composed of one carbon and two oxygen atoms.
☛ O₂: Chemical formula for Diatomic Oxygen, essential for aerobic respiration in living organisms.
☛ Water exhibits anomalous expansion and reaches its maximum density at 4°C.
☛ Heavy water, used as a moderator and coolant in nuclear reactors, has the chemical formula D₂O (Deuterium oxide).
Important One-Liners for Upcoming Exams:
☛ What is the pH value of pure water at 25°C? → 7 (Neutral)
☛ Which type of intermolecular force is responsible for the unusually high boiling point of water? → Hydrogen bonding
☛ What is the ratio by mass of Hydrogen to Oxygen in water? → 1 : 8
☛ What is the molecular mass of a water molecule? → Approximately 18 u
☛ Who demonstrated that water is composed of hydrogen and oxygen? → Henry Cavendish