Question

Metals above hydrogen in the activity series react with acids to give what two products? What general type of reaction does this exemplify?

Short answer

Metals react with acids to produce hydrogen gas and a salt. This is a single replacement reaction.

Step-by-step solution

Understanding the Activity Series

The activity series is a list of elements organized by their reactivity. Metals above hydrogen in this series can displace hydrogen from acids, whereas those below hydrogen cannot.

Identifying Metal-Acid Reaction Products

When a metal reacts with an acid, it typically produces hydrogen gas and a salt. The metal displaces hydrogen from the acid, capturing the non-metal part of the acid to form a salt.

Example of the Reaction

For instance, if zinc (Zn) reacts with hydrochloric acid (HCl), the products are zinc chloride (ZnCl_2) and hydrogen gas (H_2):\[ \text{Zn} + 2 \text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \up \] This reaction shows the metal replacing hydrogen and forming a new compound with the non-metal part of the acid.

Classifying the Reaction Type

This type of reaction is categorized as a single replacement reaction or single displacement reaction. In this type of reaction, one element (a metal) replaces another element (hydrogen) in a compound, resulting in the release of hydrogen gas.

Key concepts

Activity Series

The activity series is a tool used by chemists to predict the outcome of reactions involving metals and acids. It is essentially a chart that ranks metals (and some non-metals) by their reactivity. Metals high on the activity series list are more reactive, meaning they are more willing to participate in chemical reactions.

Those metals that are above hydrogen in the activity series are particularly important in single replacement reactions with acids. They are capable of displacing hydrogen ions from an acid, leading to the release of hydrogen gas.

If a metal is below hydrogen on the activity series, it will not react with acids under normal conditions to produce hydrogen gas. This hierarchy is essential for predicting whether a metal will react with an acid. For instance:

• Metals like potassium, sodium, and calcium are very reactive and readily displace hydrogen.
• On the other hand, metals like gold and silver, positioned below hydrogen, do not react with acids to produce hydrogen gas.

Metal-Acid Reaction

When a metal reacts with an acid, a specific type of chemical reaction occurs that produces two specific products: hydrogen gas and a salt.

This happens because the metal takes the place of hydrogen in the acid. The metal bonds with the non-metal part of the acid, forming a compound known as a salt. Meanwhile, hydrogen ions (H⁺) are released as hydrogen gas (H₂).

For example, if you react zinc (Zn) with hydrochloric acid (HCl), zinc displaces the hydrogen forming zinc chloride (ZnCl₂) and hydrogen gas. This can be represented by the reaction:

• Reactants: Zn and HCl
• Products: ZnCl₂ and H₂ gas

Understanding this process is crucial in predicting the result of mixing metals with acids, especially when designing experiments or handling chemicals safely.

Single Replacement Reaction

Single replacement reactions are a type of chemical reaction where one element replaces another element in a compound. A typical example involves a metal reacting with an acid, as detailed earlier.

In these reactions, the more reactive metal displaces a less reactive element from a compound. This is also known as a single displacement reaction, and it follows a general pattern:

• A (metal) + BC (acid) → AC (salt) + B (hydrogen gas)

For instance, when zinc reacts with hydrochloric acid, zinc replaces the hydrogen to form zinc chloride and hydrogen gas as shown:
\[ \text{Zn} + 2 \text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \uparrow \]

These reactions are important not only in chemistry labs but also in industrial applications, where such reactions may be utilized for processes like metal refining or energy production.