In the flame test of a mixture of salts, a green flame with blue centre was observed, Which one of the following cations may be present?

Options

A. `Cu^(2+)`
B. `Sr^(2+)`
C. `Ba^(2+)`
D. `Ca^(2+)`

Explanation

To solve the question regarding the flame test of a mixture of salts that produces a green flame with a blue center, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Flame Test**: The flame test is a qualitative analysis technique used to identify the presence of certain metal ions based on the color of the flame produced when the metal salts are heated.

2. **Identify the Flame Color**: In this case, the flame observed is described as green with a blue center. We need to determine which cation corresponds to this specific flame color.

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