When orange solution containing `Cr_(2)O_(7)^(2-)` ion is treated with an alkali, a yellow solution is formed and when `H^(+)` ions are added to yellow solution, an orange solution is obtained. Explain why does this happen?

Explanation

To explain the phenomenon of color change when treating a solution containing the dichromate ion (\(Cr_2O_7^{2-}\)) with an alkali and then with \(H^+\) ions, we can break down the process into clear steps:

### Step 1: Understanding the Initial Solution
- The initial solution contains the dichromate ion (\(Cr_2O_7^{2-}\)), which is orange in color. This ion is typically found in acidic solutions.

### Step 2: Reaction with Alkali
- When an alkali (such as sodium hydroxide, \(NaOH\)) is added to the orange solution, a reaction occurs that converts the dichromate ion into the chromate ion (\(CrO_4^{2-}\)).
- The reaction can be represented as:
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