Read the following and answer any four questions
Sohan went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was sad but after a futile argument, the man beat a hasty retreat.
Which of the following is used for dissolution of gold?

Options

A. Hydrochloric acid
B. Sulphuric acid
C. Nitric acid
D. Aqua regia

Explanation

To answer the question regarding which reagent is used for the dissolution of gold, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the reagent that is specifically used to dissolve gold. This is a common process in gold refining and recovery.

2. **Identifying the Reagent**: The reagent known for dissolving gold is called **aqua regia**. Aqua regia is a highly corrosive mixture of acids.

3. **Composition of Aqua Regia**: Aqua regia is made by mixing two strong acids: **nitric acid (HNO3)** and **hydrochloric acid (HCl)**. The typical ratio for mixing these acids is **3 parts hydrochloric acid to 1 part nitric acid**.

4. **Application of Aqua Regia**: This reagent is not only used for dissolving gold but also for dissolving platinum and is widely used in metal refining processes.

5. **Conclusion**: Therefore, the correct answer to the question is that **aqua regia** is used for the dissolution of gold.

### Final Answer:
The reagent used for the dissolution of gold is **aqua regia**.

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