Which metal would react spontaneously with hydrochloric acid?

Which metal would react spontaneously with hydrochloric acid?

• A. Gold
• B. Zinc
• C. Copper
• D. Silver

Answer: (B)

Metals react with acids by displacing hydrogen if they are more reactive than hydrogen in the activity series. When a metal is above hydrogen, it donates electrons to H+, forming hydrogen gas, and the metal forms its chloride salt with the acid. Zinc fits this pattern because it is more reactive than hydrogen. With hydrochloric acid, zinc donates electrons to the hydrogen ions and the reaction produces zinc chloride and hydrogen gas: Zn + 2 HCl → ZnCl2 + H2. This shows the reaction happens readily at room temperature. Gold, copper, and silver are less reactive than hydrogen in this context, so they don’t spontaneously react with hydrochloric acid under normal conditions. Gold and silver are particularly inert, and copper typically doesn’t react with dilute hydrochloric acid unless an additional oxidizing agent is present.

Metals react with acids by displacing hydrogen if they are more reactive than hydrogen in the activity series. When a metal is above hydrogen, it donates electrons to H+, forming hydrogen gas, and the metal forms its chloride salt with the acid.

Zinc fits this pattern because it is more reactive than hydrogen. With hydrochloric acid, zinc donates electrons to the hydrogen ions and the reaction produces zinc chloride and hydrogen gas: Zn + 2 HCl → ZnCl2 + H2. This shows the reaction happens readily at room temperature.

Gold, copper, and silver are less reactive than hydrogen in this context, so they don’t spontaneously react with hydrochloric acid under normal conditions. Gold and silver are particularly inert, and copper typically doesn’t react with dilute hydrochloric acid unless an additional oxidizing agent is present.