Question

The production of a new substance, most probably hydrogen, from the reaction of two reactants is described. When a few drops of the liquid product are evaporated on a watch glass, a white residue is left. Conversely, when a few drops of the liquid hydrochloric acid are evaporated on a watch glass, there is no residue. This proves that a new product (hydrogen gas) and (white powder, zinc chloride) is produced instead of zinc being physically dissolved in hydrochloric acid.

What conclusion can be drawn from the information provided?

a. Hydrogen gas is produced, and zinc chloride is formed as a white powder.
b. Hydrogen gas is produced, and zinc is physically dissolved in hydrochloric acid.
c. No reaction occurs between the two reactants.
d. Zinc chloride is formed as a white powder, and zinc is physically dissolved in hydrochloric acid.

Answer 1

The information provided suggests that a chemical reaction occurs between the two reactants, resulting in the production of hydrogen gas and zinc chloride.

Step-by-step explanation:

The information provided suggests that a chemical reaction occurs between the two reactants. When a few drops of the liquid product (presumably hydrogen gas) are evaporated, a white residue (zinc chloride) is left. On the other hand, when a few drops of liquid hydrochloric acid are evaporated, no residue is left.

This indicates that a new product (hydrogen gas) and zinc chloride are formed, rather than zinc being physically dissolved in hydrochloric acid. Therefore, the correct conclusion is that option a. Hydrogen gas is produced, and zinc chloride is formed as a white powder.