Grade 6 → Acids, Bases and Salts ↓
Definition of Salt
Salts are an essential part of chemistry, especially when studying acids and bases. In this guide, we'll learn what salts are, how they're formed, and their importance in the world around us. Let's dive into a simple understanding of salts and their roles in chemistry.
What are salts?
In simple terms, salts are compounds formed by the neutralization reaction between an acid and a base. When an acid and a base come together, they neutralize each other. The acid donates a hydrogen ion (H +
), and the base accepts it, resulting in the formation of salt and water.
Simplified explanation and examples
To understand this better, let's look at a basic chemical reaction:
HCl + NaOH → NaCl + H 2 O
In this reaction, hydrochloric acid (HCl
) reacts with sodium hydroxide (NaOH
), a base. The result is sodium chloride (NaCl
), which is a salt, and water (H 2 O
).
This can be viewed as follows:
H + + Cl - + Na + + OH - → NaCl + H 2 O
Here, the hydrogen ion (H +
) from the acid combines with the hydroxide ion (OH -
) from the base to form water. The sodium ion (Na +
) combines with the chloride ion (Cl -
) to form sodium chloride, which is common table salt.
Formation of salts
Salts are produced by replacing hydrogen ions in acids with metal ions or other cations. Below are several ways in which salts are formed:
1. Neutralization reactions
As mentioned above, the neutralization reaction between an acid and a base produces salt and water. Here's another example:
H 2 SO 4 + Mg(OH) 2 → MgSO 4 + 2H 2 O
In this reaction, sulfuric acid (H 2 SO 4
) reacts with magnesium hydroxide to form magnesium sulfate (MgSO 4
) and water.
2. Reaction of acids with metals
When acids react with metals some salts are formed:
2HCl + Zn → ZnCl2 + H2
Here, hydrochloric acid reacts with zinc to form zinc chloride and hydrogen gas. In this type of reaction, the metal replaces the hydrogen in the acid and a salt is formed.
3. Reaction of acids with metal oxides
Metal oxides can also react with acids to form salts:
2HCl + CuO → CuCl2 + H2O
This is the reaction between hydrochloric acid and copper(II) oxide, forming copper(II) chloride and water.
4. Reaction of acids with metal carbonates
Acids react with metal carbonates to form salt, water, and carbon dioxide:
2HCl + Na2CO3 → 2NaCl + H2O + CO2
In this case, the hydrochloric acid reacts with sodium carbonate, forming sodium chloride, water, and carbon dioxide gas.
Types of salts
Salts are classified based on the way they are formed and their chemical properties. Here are some types:
1. Common salt
Normal salts are formed when all the replaceable hydrogen ions of an acid are replaced by metal ions or other cations. For example:
HCl + NaOH → NaCl + H2O
2. Acid salts
Acid salts are formed when not all of the hydrogen ions in an acid are replaced. Often, these salts can act as acids in water. For example:
NaHSO4
Sodium bisulfate is an acidic salt of sulfuric acid.
3. Basic salts
Alkaline salts are formed by incomplete neutralization of a base. For example:
Zn(OH)Cl
Zinc hydroxide chloride is a basic salt.
Importance of salts
Salt plays an important role in everyday life as well as in scientific processes. Some prominent examples include:
- In the kitchen: Common salt (
NaCl
) is widely used in cooking. - In agriculture: Salts such as ammonium nitrate are used as fertilizers.
- In industries: Salts such as borax and sodium carbonate are used in manufacturing and cleaning.
Conclusion
Salts are fascinating compounds that form from the interaction between acids and bases and serve many purposes in science and everyday life. From our kitchens to large industrial applications, salts are important for many processes. Understanding salts helps us understand more about the chemical reactions and compounds that make up the world.