What property of the following reaction might be qualitatively measured to follow the rate of reaction?

A) C(s) + H20(g) > H2(g) + CO(g)
B) Cu(s) + 2Ag+(aq) > Cu2+(aq) + 2Ag(s)

A. The pressure since there is more gas on the right side than the left side.

B. Color. The Cu^+2 ion is blue. All of the other materials (in solution) are colorless.

ohhhh ! yes #2 makes perfect sense.

but, how would you test for pressure?
a burning splint test?

Hook a pressure gauge up to the enclosed vessel. As the reaction proceeds the pressure will increase.

The property of a reaction that can be qualitatively measured to follow the rate of reaction is the concentration of reactants or products.

In the case of the reaction A) C(s) + H20(g) > H2(g) + CO(g), you would need to monitor the concentrations of C, H2O, H2, and CO to determine how the reaction proceeds over time.

For reaction B) Cu(s) + 2Ag+(aq) > Cu2+(aq) + 2Ag(s), you would need to monitor the concentrations of Cu, Ag+, and Cu2+ to determine the rate of reaction.

To measure the concentration of a compound, you can use various techniques such as spectroscopy, titration, or chromatography. These methods involve collecting samples at different time intervals and then analyzing them to determine the concentration of the specific compound of interest. By measuring the concentration of the reactants or products at different time points, you can observe how the concentration changes over time and get an indication of the rate of reaction.