SSC GD 2025 PYQ — Question 26

The correct answer is option 4 i.e. Iron, methane, and sea water.

• Iron, methane and seawater—the correct order of materials placed one after the other according to the order of element, compound and homogeneous mixture.
• Iron (Fe): An element (a pure substance consisting of only one type of atom).
• Methane (CH₄): A compound (a pure substance formed when two or more different elements are chemically bonded in a fixed ratio).
• Sea water: A Homogeneous Mixture (a mixture, or solution, of water, dissolved salts, and other substances that has a uniform composition throughout).

Other Options:

• Salt, iron and sea water: Incorrect. Salt (Sodium Chloride, (NaCl) is a Compound, not an element, breaking the sequence.

• Mercury, iron, and diluted acid: Incorrect. While Mercury (Hg) and Iron (Fe) are elements, diluted acid (e.g., acid dissolved in water) is a homogeneous mixture, not a compound.

• Mercury, salt, and milk: Incorrect. Mercury (Hg) is an element, and salt (NaCl) is a compound.¹⁰ However, milk is a heterogeneous mixture (specifically, a colloid/emulsion) because its components (fat globules, proteins) are not uniformly mixed at a microscopic level and can separate over time.¹¹