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 non-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 burns in oxygen.

### Step-by-Step Solution:

1. **Identify the Element X**:
- The problem states that X is an element in the form of a powder that burns in oxygen. This suggests that X is likely a non-metal, as many non-metals can burn in oxygen to form oxides.

2. **Determine the Product of Combustion**:
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