Question

Determine which of the following metals can react with acid: (a) \(\mathrm{Au},(\mathrm{b}) \mathrm{Ni},(\mathrm{c}) \mathrm{Zn},(\mathrm{d}) \mathrm{Ag},(\mathrm{e}) \mathrm{Pt}\).

Short answer

Nickel (Ni) and Zinc (Zn) can react with acids.

Step-by-step solution

Understand the Reaction

When a metal reacts with an acid, it typically displaces hydrogen to form a salt and hydrogen gas. This reaction often depends on the metal's position in the activity series. Metals above hydrogen in the activity series can displace hydrogen from acids.

Identify the Activity Series

Metals more reactive than hydrogen in the activity series include metals like zinc (Zn) and nickel (Ni). Metals less reactive than hydrogen include gold (Au), silver (Ag), and platinum (Pt).

Compare Each Metal with Hydrogen

(a) Gold (Au) is less reactive than hydrogen and does not react with acids. (b) Nickel (Ni) is more reactive than hydrogen and can react with acids. (c) Zinc (Zn) is more reactive than hydrogen and can react with acids. (d) Silver (Ag) is less reactive than hydrogen and does not react with acids. (e) Platinum (Pt) is less reactive than hydrogen and does not react with acids.

Final List of Reactive Metals

Based on the activity series comparison, the metals that can react with acids from the given list are nickel (Ni) and zinc (Zn).

Key concepts

Understanding the Activity Series

The activity series is a crucial tool in predicting metal reactivity with other substances, such as acids. The activity series is a list of metals arranged in order of decreasing reactivity. This means that metals at the top of the list are more reactive than those at the bottom.
For a metal to displace another element in a compound, the metal must be higher in the activity series than the element it is displacing. This is particularly relevant when dealing with acids, where metals displace hydrogen gas.

• Metals like potassium and sodium are at the top due to their high reactivity.
• Metals such as gold and platinum are at the bottom, indicating their resistance to reaction.

This order allows us to predict whether a metal will react based solely on its position relative to hydrogen, guiding experiments and industrial applications.

Exploring Displacement Reactions

Displacement reactions, also known as single displacement reactions, occur when a more reactive metal displaces a less reactive element from a compound. This type of reaction is common between metals and acids.
In such reactions, the more active metal will take the place of an element within the compound (often hydrogen when acids are involved).

• If metal A is more reactive than metal B, when A is added to a solution containing a compound of B, it will replace B in the compound, resulting in a displaced substance.
• The basic formula for this reaction is: \[ \text{Metal + Acid} \rightarrow \text{Salt + Hydrogen gas} \]

Displacement reactions are not only vital in chemistry but also in various real-world applications, including metal extraction and recycling.

Hydrogen Displacement and Metal Reactions

Hydrogen displacement is a type of reaction where metals react with acids to eject hydrogen gas. In these reactions, the metal replaces the hydrogen in the compound, forming a new compound and releasing hydrogen.
It is essential to understand that only metals more reactive than hydrogen in the activity series can successfully displace hydrogen in this way.

• For example, zinc reacts with hydrochloric acid to produce zinc chloride and hydrogen gas: \[ \text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2 \]
• Metals such as gold or silver will not participate in such reactions because they are less reactive than hydrogen.

This concept is critical for industries that utilize hydrogen gas and need to harness it efficiently through chemical reactions.

Examining Metal Reactivity

Metal reactivity is a measure of how readily a metal will react with substances like acids, water, or oxygen. It is a fundamental concept to understand as it informs safe handling, storage, and practical applications of metals.

• The reactivity of metals can influence decisions in metal selection for industrial use, such as corrosion resistance, strength, and conductivity.
• Reactions with acids showcase a practical aspect of metal reactivity, where only those that are more reactive than hydrogen are chosen when preparing solutions that require reaction-based products.

For example, in the provided exercise, nickel and zinc are more reactive than hydrogen and can thus react with acids to form salts and release hydrogen gas. This knowledge helps predict and control chemical reactions in analytical and industrial chemistry.