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Q78 (NDA-II/2013) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Basic chemical principles Answer Verified

A mixture of sodium chloride and naphthalene can be separated by

Result
Your answer: —  Â·  Correct: C
Explanation

A mixture of sodium chloride (NaCl) and naphthalene can be effectively separated using sublimation. Naphthalene is a volatile organic compound that possesses the unique physical property of transitioning directly from a solid state to a gaseous state upon heating, without passing through a liquid phase. In contrast, sodium chloride is a non-sublimable ionic compound with a very high melting point, held together by strong electrostatic forces. When the mixture is heated, naphthalene sublimes and can be collected as pure crystals on a cool surface, leaving the solid sodium chloride behind in the original container. While sodium chloride is soluble in water, naphthalene is not, making water extraction a theoretical alternative; however, sublimation is the standard laboratory method for separating sublimable substances from non-sublimable salts.

Sources

  1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > 3.3 HOW DO METALS AND NON-METALS REA ALS REACT? > p. 47
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