If a hydrate of the formula MCl * xH2O decomposes when heated to produce HCL, what change would you expect to occur when a piece of litmus paper is held in the path of the vapor released?

Since HCl is an acid when dissolved in water (the water probably comes off at the same time), I would expect the litmus paper to show an acid color. Do you know what that color is?

Is it red?

Right you are.

Bases turn red litmus blue.
Acids turn blue litmus red.

Thank you so much!

To determine the change that would occur when a piece of litmus paper is held in the path of the vapor released during the decomposition of the hydrate, we need to understand the effect of HCl on litmus paper.

Litmus paper is a pH indicator that changes color in the presence of acids or bases. It turns red in the presence of acids and blue in the presence of bases.

Since the hydrate decomposes to produce HCl, which is an acid, we can expect the litmus paper to change color. Specifically, it will turn from its initial color (usually blue) to red when exposed to the HCl vapor.

To determine this, you can perform a simple experiment:
1. Obtain a piece of litmus paper.
2. Set up a heat source, such as a Bunsen burner or a hot plate.
3. Place the hydrate in a heat-resistant container, such as a crucible or a test tube.
4. Heat the hydrate gently until the decomposition occurs and vapor is released.
5. Hold the piece of litmus paper in the path of the released vapor.
6. Observe the color change of the litmus paper.
7. If the litmus paper turns red, it indicates the presence of HCl, confirming that the hydrate decomposes to produce HCl.

It's important to note that handling HCl can be hazardous, so appropriate safety precautions should be taken, such as working in a well-ventilated area and wearing appropriate protective equipment like gloves and goggles.