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 it will not conduct electricity unless it is carbon in the form of ____

Explanation

To solve the question, we need to analyze the information provided about element X and its properties.

1. **Identify the Element**: The question states that X is a powder that burns in oxygen and produces a product that is soluble in water. This suggests that X is likely a non-metal, as many non-metals (like sulfur or phosphorus) can burn in oxygen to form acidic or basic oxides that are soluble in water.

2. **Understanding Conductivity**: The question specifically asks about the conductivity of non-metals. Generally, non-metals are poor conductors of electricity because they lack free electrons that can move and carry an electric charge.

3. **Exception for Carbon**: However, the question mentions that if X is a non-metal, it will not conduct electricity unless it is carbon in a specific form. The only form of carbon that is known to conduct electricity is graphite. Graphite has a structure that allows for free electrons to move, making it a good conductor of electricity.

...