When orange filter paper is dipped into SO2 gas, you will see a color change to a lighter shade of orange or even a pale yellow.

Here's why:

* SO2 is acidic: Sulfur dioxide (SO2) is a colorless gas that dissolves in water to form sulfurous acid (H2SO3).

* Acid-base reaction: The acidic SO2 reacts with the orange dye on the filter paper. This reaction changes the chemical structure of the dye, causing a shift in the color it absorbs and reflects.

* Color change: The change in the dye's structure results in a change in the color perceived. The orange color, which is a combination of red and yellow wavelengths, is likely to lose some of its red component due to the reaction, resulting in a lighter orange or a more yellowish hue.

Important Note: The specific color change will depend on the type of orange dye used on the filter paper. Some dyes may be more sensitive to SO2 than others.