Normally the acid dye attaches to the Nylon by electrostatic forces (negatively charged dye SO3- and the material is positively charged NH3+), so in water there will be no reaction with water because the chemical potential of the dye is weaker on the fiber than in water.

To determine whether acid dye absorbed in colored nylon fabric reacts with water molecules after being placed in water, you can perform a simple experiment. Here's a basic outline of the experimental procedure:

Materials Needed:

Colored nylon fabric samples dyed with acid dye

Distilled water

Beakers or containers

Dropper or syringe

pH indicator solution (optional)

pH meter or pH test strips (optional)

Microscope (optional)

By conducting this experiment and analyzing the results, you can gain insights into whether acid dye absorbed in colored nylon fabric reacts with water molecules when placed in water.

Procedure:

a-Prepare your colored nylon fabric samples. Ensure that they are dyed with acid dye and that the dye has been adequately absorbed into the fabric.

b-Fill a beaker or container with distilled water.

c-Place the nylon fabric samples into the water. Ensure that the fabric is fully submerged.

d-Observe the fabric samples over time. You can record your observations at regular intervals (e.g., every 5 minutes) for a set duration.

e-Look for any visible changes in the fabric, such as color bleeding or fading. This could indicate that the acid dye is reacting with water molecules.

f-If you have access to a pH indicator solution, you can test the pH of the water before and after immersing the fabric samples. Acid dyes typically contain acidic groups that can alter the pH of the water when they react with water molecules. A decrease in pH could suggest a reaction between the dye and water.

g-Optionally, you can examine the fabric samples under a microscope to look for any structural changes or interactions between the dye molecules and water molecules at a microscopic level.

h-Repeat the experiment with control samples, such as undyed nylon fabric or fabric dyed with a different type of dye (e.g., basic dye), to compare the results and confirm any observed reactions specific to the acid dye.

Dear Dr Neji Ladhari

Thanks for your guidance.

Dear Yohannes Asmare Fesseha

Thanks for your answer, I will try this method in the lab.