3.2.3 - What happens when Metals react with Acids?
Enroll to start learning
You’ve not yet enrolled in this course. Please enroll for free to listen to audio lessons, classroom podcasts and take practice test.
Interactive Audio Lesson
Listen to a student-teacher conversation explaining the topic in a relatable way.
Understanding the Reaction of Metals with Acids
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Today, we're discussing what happens when metals react with acids. Can anyone tell me what they think happens during this reaction?
I think they produce something, maybe a gas?
That's correct! When metals react with acids, they typically produce hydrogen gas and a salt. For example, if we react magnesium with hydrochloric acid, we get magnesium chloride and hydrogen.
Does it happen with all metals?
Good question! Not all metals react the same way. Metals like magnesium and aluminum react vigorously, while others like copper do not react at all. This is a great example of reactivity differences.
How do we know which metals are more reactive?
We can perform experiments! By observing the rate at which gas bubbles form or the temperature change, we can rank metals by their reactivity.
So, is it always the same reaction?
Great point! Although the general reaction follows the same format, the specifics can vary. For instance, magnesium may react exothermically while iron would exhibit a slower reaction.
Remember: Magnesium, Aluminum, Zinc, and Iron show increasing reactivities with acids, while Copper shows no reaction. Let's take note of that!
Observing Reactivity in Action
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Now, let's perform an experiment. Who can tell me what to expect when we react magnesium with hydrochloric acid?
I expect to see bubbles forming.
Exactly! Those bubbles are hydrogen gas. Let’s watch as magnesium reacts.
What about aluminum? Will it react similarly?
Yes, it will also produce bubbles, but we might see that it reacts a bit more slowly compared to magnesium because of the protective oxide layer on its surface.
And iron reacts too, right?
Yes, but more slowly than zinc. It’s important to compare these performances! When we finish, we’ll make a table of our observations.
What happens if we use copper?
Good point! Nothing should happen when we add copper to hydrochloric acid. This is why copper is considered non-reactive in this case.
Let's summarize — we can classify metals based on how they react with acids, using our experimental findings!
Chemical Equations of Metal Reactions
🔒 Unlock Audio Lesson
Sign up and enroll to listen to this audio lesson
Now that we've seen these reactions, who can tell me what the general equation for a metal reacting with an acid is?
Metal plus acid gives salt and hydrogen gas!
Absolutely! And for magnesium reacting with hydrochloric acid, how would we write that?
Mg + 2HCl → MgCl₂ + H₂?
Exactly. This equation tells us about the products formed during the reaction. Always remember to balance the equations!
What about aluminum? Is it the same?
Yes, but don’t forget to adjust for the number of hydrogen ions as we would react with 6HCl for aluminum reactions.
And copper doesn't have an equation because it doesn't react?
Correct! No reaction, no equation! Understanding these processes helps us figure out how to safely handle materials in labs and industries.
For now, let's remember these equations for the metals we've tested!
Introduction & Overview
Read summaries of the section's main ideas at different levels of detail.
Quick Overview
Standard
This section discusses the reactions of metals with dilute acids, emphasizing that different metals exhibit varying reactivities, the products formed, and the specific equations for these reactions. It highlights magnesium, aluminum, zinc, and iron as examples of metals that react with dilute hydrochloric acid while noting that copper does not react at all.
Detailed
In this section, we explore the chemical behavior of metals when they react with acids, specifically dilute hydrochloric acid. The general reaction can be expressed as:
Metal + Dilute acid → Salt + Hydrogen
When metals such as magnesium, aluminum, and zinc react with dilute hydrochloric acid, they produce corresponding salts and hydrogen gas. The reaction is often vigorous, especially with magnesium, which results in a rapid formation of bubbles and an increase in temperature. As observed, magnesium and aluminum showcase the highest reactivity, followed by zinc and then iron, while copper remains unreactive in this context. Understanding these reactions is crucial in predicting how different metals will behave in various scenarios, particularly in industrial and lab applications.
Youtube Videos
![🧪How Do Acids React With Metals?🧪 [HCl + Mg] | Class 10 Science Chapter 2 | Learn Practically](https://img.youtube.com/vi/UTTSie9ujis/mqdefault.jpg)
Audio Book
Dive deep into the subject with an immersive audiobook experience.
General Reaction of Metals with Acids
Chapter 1 of 4
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
You have already learnt that metals react with acids to give a salt and hydrogen gas.
Metal + Dilute acid → Salt + Hydrogen
Detailed Explanation
When metals come in contact with acids, they undergo a chemical reaction. This reaction produces a salt and hydrogen gas. For instance, when zinc reacts with hydrochloric acid, zinc chloride (a salt) and hydrogen gas are produced. This can be represented by the equation:
Zn + 2HCl → ZnCl₂ + H₂
This general reaction indicates that acids can effectively react with metals, showcasing their chemical reactivity.
Examples & Analogies
Think of the reaction like a trade where metals exchange their properties with acids. Just as when two friends trade their toys, metals 'trade' their electrons with acids to form new substances, namely the salts and hydrogen gas, much like getting something new in return.
Experiment with Metal Samples
Chapter 2 of 4
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
n Collect all the metal samples except sodium and potassium again. If the samples are tarnished, rub them clean with sand paper. CAUTION: Do not take sodium and potassium as they react vigorously even with cold water.
n Put the samples separately in test tubes containing dilute hydrochloric acid.
n Suspend thermometers in the test tubes, so that their bulbs are dipped in the acid.
n Observe the rate of formation of bubbles carefully.
n Which metals reacted vigorously with dilute hydrochloric acid?
n With which metal did you record the highest temperature?
n Arrange the metals in the decreasing order of reactivity with dilute acids.
Detailed Explanation
In this experiment, students are advised to collect various metal samples (excluding very reactive ones like sodium and potassium). They then place these metals in dilute hydrochloric acid and observe the reactions. The formation of bubbles indicates the release of hydrogen gas and serves as a measure of how vigorously a metal reacts with the acid. By comparing the temperature changes registered by the thermometers in the test tubes, students can gauge which metal is the most reactive.
Examples & Analogies
Imagine testing how quickly different types of balloons inflate. Each metal reacts like a balloon, filling with the 'air' (hydrogen) rapidly or slowly. The more vigorously a balloon expands, the more reactive the metal is with the acid.
Observations and Reaction Equations
Chapter 3 of 4
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
Write equations for the reactions of magnesium, aluminium, zinc and iron with dilute hydrochloric acid. Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO₃ is a strong oxidising agent. It oxidises the H produced to water and itself gets reduced to any of the nitrogen oxides (N₂O, NO, NO₂). But magnesium (Mg) and manganese (Mn) react with very dilute HNO₃ to evolve H gas.
Detailed Explanation
Different metals produce different reactions with hydrochloric acid. For example,
- Magnesium: Mg + 2HCl → MgCl₂ + H₂
- Aluminium: 2Al + 6HCl → 2AlCl₃ + 3H₂
- Zinc: Zn + 2HCl → ZnCl₂ + H₂
- Iron: Fe + 2HCl → FeCl₂ + H₂
However, nitric acid does not produce hydrogen gas because it acts differently than hydrochloric acid; it reacts as an oxidizer, converting hydrogen ions to water instead. This shows that while many metals react with acids to release hydrogen gas, nitric acid’s strong oxidizing nature inhibits this reaction.
Examples & Analogies
Think of different foods reacting with vinegar (similar to acids). Just as some foods spoil quickly when mixed with vinegar, some metals react faster with hydrochloric acid than others. However, if you try to pickle them with a different method (like nitric acid), some won't spoil (no hydrogen). This illustrates how metals can have varied reactions depending on their environment.
Reactivity Trends of Metals
Chapter 4 of 4
🔒 Unlock Audio Chapter
Sign up and enroll to access the full audio experience
Chapter Content
You must have observed in Activity 3.11, that the rate of formation of bubbles was the fastest in the case of magnesium. The reactivity decreases in the order Mg > Al > Zn > Fe. In the case of copper, no bubbles were seen and the temperature also remained unchanged. This shows that copper does not react with dilute HCl.
Detailed Explanation
From the experiment, students can determine a line of reactivity among metals. Magnesium reacts most vigorously to produce hydrogen gas, while copper shows no reaction. This clearly indicates that metals can be arranged in a series based on their reactivity when coming in contact with acids, reflecting their ability to release hydrogen gas. The general trend can be summarized as magnesium being the most reactive, followed by aluminum, zinc, and then iron. Copper is an exception and does not react at all with dilute hydrochloric acid.
Examples & Analogies
Consider a race where athletes have different speeds. Magnesium is like the fastest runner, quickly getting to the finish line (producing bubbles), while copper is like a spectator that just stays put and doesn't run at all. This race analogy helps understand how varying reactivities can be observed in this metal 'race' when mixed with acids.
Key Concepts
-
Metals react with dilute acids to produce salts and hydrogen gas.
-
The rate of reaction varies among different metals, such as magnesium, aluminum, zinc, and iron.
-
Copper does not react with dilute hydrochloric acid.
-
Chemical reactions can be represented with balanced equations.
Examples & Applications
When magnesium reacts with hydrochloric acid, it produces magnesium chloride and hydrogen gas: Mg + 2HCl → MgCl₂ + H₂.
Zinc reacts with hydrochloric acid yielding zinc chloride and hydrogen: Zn + 2HCl → ZnCl₂ + H₂.
Memory Aids
Interactive tools to help you remember key concepts
Rhymes
When metals meet acid, watch the reaction flow; salts and some gas, it's a great show!
Stories
Once there was a magnesium who dived into the acid sea, bubbles of hydrogen rose quickly, as merry as can be!
Memory Tools
Remember MAZI for metals: Magnesium, Aluminum, Zinc, Iron - react with acids!
Acronyms
GAS
for Gas (hydrogen)
for Acid (hydrochloric)
for Salt (metal chloride) - what happens in reactions!
Flash Cards
Glossary
- Dilute Acid
An acid that has been mixed with water to decrease its concentration.
- Salt
A compound formed from the reaction of an acid with a base or metal.
- Reactivity
The tendency of a substance to undergo chemical reaction, either by itself or with other materials.
- Hydrogen Gas
A colorless, odorless gas produced in certain chemical reactions, such as when metals react with acids.
Reference links
Supplementary resources to enhance your learning experience.