In the ring test for identification of nitrate ion, what is the formula of the compound responsible for the brown ring formed at the interface of the two liquids ?

Explanation

To determine the formula of the compound responsible for the brown ring formed at the interface of two liquids in the ring test for identification of nitrate ion, we can follow these steps:

### Step 1: Understand the Ring Test
The ring test is a qualitative analysis method used to identify the presence of nitrate ions (NO3-) in a solution. The test involves adding a specific reagent to the solution containing the nitrate ions.

**Hint:** The ring test is specifically designed for detecting nitrate ions.

### Step 2: Identify the Reagent Used
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