Understanding Metal Reactions with Acids

When most reactive metals react with dilute acids, a chemical reaction takes place which produces a salt and hydrogen gas. This is a type of single displacement reaction where the metal displaces the hydrogen from the acid.

General Reaction of Metals and Acids

The general equation representing the reaction between a metal and an acid is:

Metal + Acid → Salt + Hydrogen gas

For example, when zinc metal reacts with hydrochloric acid, the reaction is:

\(\text{Zn(s)} + \text{2HCl(aq)} \rightarrow \text{ZnCl}_2\text{(aq)} + \text{H}_2\text{(g)}\)

Here, zinc chloride (\(\text{ZnCl}_2\)) is the salt formed, and hydrogen (\(\text{H}_2\)) is the gas released.

Another example is the reaction between magnesium and sulfuric acid:

\(\text{Mg(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{MgSO}_4\text{(aq)} + \text{H}_2\text{(g)}\)

Magnesium sulfate (\(\text{MgSO}_4\)) is the salt and hydrogen gas is produced.

Analyzing the Options

• Option 1: Salt and chlorine
  While salts are formed, chlorine gas is not a typical product of the reaction between metals and common acids like hydrochloric acid, sulfuric acid, or nitric acid.
• Option 2: A salt and base
  Acids react with bases in a neutralization reaction to form salt and water, not a salt and a base from a metal reaction.
• Option 3: A salt and hydrogen
  As explained above, this is the standard outcome when a reactive metal reacts with a dilute acid.
• Option 4: Salt and water
  Salt and water are the products of an acid reacting with a base (neutralization), or sometimes metal oxides reacting with acids, but not generally when a metal itself reacts with an acid.

Therefore, the products of the reaction between metals and acids are a salt and hydrogen gas.

Revision Table: Metal Reactions with Acids

Additional Information: Reactivity Series and Acid Reactions

Not all metals react with acids. The reactivity of a metal determines whether it can displace hydrogen from an acid. Metals higher in the reactivity series (like Potassium, Sodium, Calcium, Magnesium, Aluminium, Zinc, Iron, Lead) are generally reactive enough to react with dilute acids. Metals below hydrogen in the reactivity series (like Copper, Silver, Gold, Platinum) typically do not react with dilute non-oxidizing acids to produce hydrogen gas.

Some acids, like concentrated nitric acid, react differently due to their oxidizing properties and may not produce hydrogen gas even with reactive metals.