X is an element in the form of a powder. X burns in oxygen and the product is soluble in water. The solution is tested with litmus. Write down only the word, which will correctly complete the following sentence.
If X is a metal, then the litmus will turn ____

Explanation

To solve the question, we need to analyze the information given about the element X and its behavior when it reacts with oxygen.

### Step-by-Step Solution:

1. **Identify the Element X**:
- The element X is in the form of a powder and burns in oxygen. This indicates that X is likely a metal, as many metals react with oxygen to form oxides.

2. **Determine the Product**:
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