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Q88 (CDS-II/2010) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Applied everyday chemistry Answer Verified

A woman desires to clean the surface’ of her gold ornaments by a chemical approach. For this she requires to use

Result
Your answer:  ·  Correct: A
Explanation

To chemically clean gold ornaments, aqua regia is used because it is one of the few reagents capable of dissolving gold [1]. Aqua regia is a freshly prepared mixture of concentrated hydrochloric acid (HCl) and concentrated nitric acid (HNO3) in a 3:1 ratio [1]. While neither acid can dissolve gold individually, their combination allows the nitric acid to act as an oxidizer while the chloride ions from HCl form stable chloroaurate complexes, effectively stripping the outer layer of the metal [1]. This process removes surface impurities and tarnish, restoring the gold's luster, though it results in a slight loss of gold mass as the surface layer dissolves into the solution [1]. Other options like concentrated sulfuric acid or sodium hydroxide are not standard for dissolving or cleaning the surface of solid gold ornaments in this specific chemical context.

Sources

  1. [1] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > p. 44
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