Acids Bases and Salts

Acids, bases and salts affect chemistry as well as our day to day life. They can be easily identified by their taste; that is acids taste sour and bases taste bitter and salts themselves have salty taste.

Acids are usually found in many substances including various food items but their presence in many fruits is very prominent, for example:

Apart from these, there are some acids which are widely used in the laboratory, like hydrochloric acid, sulphuric acid and nitric acid.

Usually bases are found in household cleaners only to clean grease from the windows and the floors and it is also found in soaps, toothpaste, egg whites, dish washing liquids and household ammonia.

Our body contains some very common acids in the stomach like the dilute hydrochloric acid, which causes food indigestion. When the contents of our stomach become too acidic, we usually get indigestion and a burning sensation in our stomach.

Acids and bases also regulate some metabolic activities in the human body through the process of equilibrium. Bee stings are acidic in nature while the wasp stings are alkaline in nature. 

All acids when reacted with metals generate hydrogen gas. Hydrogen is usually common to all acids.

Acid + Metal = Salt + Hydrogen

Properties of Acids

• Acid is a compound which yields hydrogen ion (H+), when dissolved in water.

            HCl + H2O → H+ + Cl-

• Acid is sour to the taste and it is corrosive in nature. The pH of acids is less than 7.            

• All acids react with metal to release hydrogen gas. For example, zinc metal reacts with hydrochloric acid to form zinc chloride and hydrogen gas.

            Zn + 2HCl → ZnCl₂ + H₂

• When acids react with limestone (CaCO₃), it produces carbon dioxide. For example,HCl reacts with limestone to produce carbonic acid and calcium chloride.

            CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O

• Acids are classified into organic and inorganic acids. The best example of organic acid is acetic acid CH₃COOH, and inorganic acids are those which are produced from minerals; for example, sulphuric acid H₂SO₄, and hydrochloric acid, etc.

• Acid usually converts blue litmus paper to red litmus paper.

• Acids have a tendency to quickly corrode the metal surfaces.     

On the Basis of Number of Hydrogen Ion, Acids can be Classified as:

1. Monoprotic Acid – They can produce one mole of 

\[H^{+}\] ions per mole of acid, ex - HCL.

2. Diprotic Acid – They can produce two moles of 

\[H^{+}\] ions per mole of acid, ex - \[H_{2}SO_{4}\]

3. Triprotic Acid – They produce three moles of 

\[H^{+}\] ions per mole of acid, ex - \[H_{3}PO_{4}\]

On the Basis of Strengths to Donate Hydrogen Ions, Acids can be Classified as:

Strong Acids: These acids get completely (100%) ionized in the aqueous solutions. Thus, at equilibrium, the concentration of acid molecules becomes very less and concentration of hydrogen ion reaches to the maximum; for example,

HCl,HNO3,HClO4

Weak Acids: These acids are only partially ionized in solution at equilibrium state. At equilibrium state, molecules of acid are present in a considerable amount and the concentration of hydrogen ion is less, for example,

HF,CH3COOH

Properties of Bases:

• Bases are compounds that yield hydroxide ion

• (OH−)

• , when it is dissolved in water.

• Bases are bitter in taste and are corrosive in nature. They usually feel slippery and very soapy.

• Bases are good conductors of electricity and usually show a pH value of more than 7.

• Bases react with oils and grease to form molecules of soap.

• Bases convert red litmus paper to blue litmus paper.

• Bases also have the tendency to corrode the surface of metals.

Strength of Bases-

Strong Bases: These are the bases which are completely ionized in water to produce hydroxide ions, e.g., sodium hydroxide

NaOH₈ \[\leftrightharpoons\] Na_(aq)⁺ + OH_(aq)^-

Weak Bases: These are the bases which are partially ionized and the equilibrium lies mostly towards the reactants side, e.g., ammonia in water

NH_3(aq) + H₂O_(l) \[\leftrightharpoons\] NH_4(aq)⁺ + OH_(aq)^-

Properties of Salts:

Salts are formed by the combination of acid and base through the neutralization reaction.

The acidic and basic nature of salts usually depends on the acid and base from which the salt evolved in a neutralization reaction.

Example:

NaOH+HCl→NaCl+H2O

HCl + NH4OH → NH4Cl + H2

CH3COOH + NaOH → CH3COONa + H

CH3COOH + NH4OH → CH3COO NH4+ H2O

The most well-known or common salt is sodium chloride or table salt which is formed by the combination of a strong base sodium hydroxide and strong acid hydrochloric acid. 

HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l)

Other examples include Epsom salt 

(MgSO4)

which is used in bath salts, ammonium nitrate

(NH4NO3)

is used as fertilizer, and baking soda

(NaHCO3)

is used in cooking.

The pH of a solution of salt also depends on the strength of acids and bases which are combined in the neutralization reaction.

Addition of Acids or Bases to Water:

The process of dissolving an acid or a base in water is highly exothermic. As this reaction usually generates a lot of heat, so there must be exclusive care taken while mixing the concentrated acids with water, especially when nitric acid or sulphuric acid is mixed with water.

Rules: The acid must be added slowly to the water with continuous and constant stirring, otherwise it can cause the mixture to splash out which in turn causes burns.

The glass container may also break due to excessive heating which can cause damage. When an acid or base is mixed with water, it results in dilution. It decreases the concentration of ions per unit volume thereby easily dissipating the effect of heat.

Uses of Acids 

Below are the uses of different types of acids: 

1. Hydrochloric Acid

• Hydrochloric acid is used in different industries for heating applications. This acid is applied to remove deposits from the inside of the boiler. 

• It is also used to clean silverware and sinks. 

2. Sulphuric Acid 

• Sulphuric acid is used to manufacture paints, dyes, drugs, and fertilizers. 

• It is also used in car batteries. 

3. Nitric Acid 

• Goldsmiths use nitric acids to clean gold and silver ornaments. 

• Nitric acid is also used for manufacturing fertilizers. 

4. Acetic Acid 

• Acetic acid can be used as a cleaning agent to clean windows, utensils, floors, etc. 

• Acetic acid is an effective ingredient to enhance the flavor of food items. 

• Acetic acid helps in the removal of stains from woodwork and carpets. 

• Acetic acid is used as a preservative in packaged foods such as sauces, ketchup, pickles, etc. 

Uses of Bases 

Here are some uses of different types of bases:

1. Calcium Hydroxide 

• Calcium hydroxide is used to neutralize acidity in the soil. 

• Calcium hydroxide is a vital ingredient in mortar and whitewash 

• It is an essential component of the Bordeaux mixture, which is used to protect agricultural crops from pests.

• Calcium hydroxide is also used to prepare dry mixes for painting. 

2. Sodium Hydroxide 

• Sodium hydroxide is used in the production of detergents, textiles, and paper. 

• Sodium hydroxide is used in households for unblocking drains. 

3. Ammonium Hydroxide 

• Ammonium hydroxide is used as a reagent in laboratories. 

• Ammonium hydroxide is also used to manufacture plastic, dye, rayon, etc. 

Learning about Acids Bases and Salts | Properties of Acids, Bases and Salts

Acids, bases, and salts are an important part of chemistry. By learning the concept of acids, bases, and salts, you can understand how these molecules react with different elements. To start learning this concept, you can refer to Vedantu’s website to get a better understanding of acids, bases, and salts. Below are some more tips to help you understand this topic: 

• Read the definitions of acids, bases, and salts thoroughly to understand their meanings. If you know the meaning of all these substances, it will be easier to understand their uses and properties. 

• Go through your textbook and read the detailed explanations of Acids, Bases and Salts to get an idea of what this topic is about. 

• Use different reference books and guides to improve your understanding of acids, bases, and salts. These books provide you with pictorial illustrations to help you understand the concept clearly. 

• Once you are done with the textbooks, you should try to answer the exercise questions given in these books. These questions will help you test your knowledge and give you an idea of the type of questions that can come in your exams. 

• To explore more questions, you should refer to sample papers and previous year question papers of chemistry. These papers will assist you in revisions and exam preparations. 

• Gain more knowledge about acids, bases, and salts from Vedantu’s online learning platform. Here, you will find all the study resources you need to study the different concepts of chemistry and enhance your knowledge.