The difference between acid and base can be stated as acids are the corrosive substances that have the ability to give a proton and accept an electron from another substance while bases are the corrosive substances which have the ability to accept a proton and give an electron to the other substances.
Acids and bases both are the types of corrosive substances. Acids are a type of ionic compounds that dissociate in water and donate a hydrogen ion (H+). Bases are also a type of ionic compounds. They also break up in the water and denote hydroxyl ion (OH-). It means to say that acids are the compounds when dissolved in water, produce a solution having a concentration of hydrogen ions greater than pure water. Conversely saying, bases are the compounds when dissolved in water produce a solution having a concentration of hydrogen ion less than the pure water.
On pH scale, acids have the pH between 0 to less than 7 while bases have the pH of greater than 7 to 14. Acids can occur any of the physical states, i.e. solids or liquids or gases depending upon the temperature, pressure and other physical conditions. Bases are mostly found in the solid form except for ammonia which occurs in the gaseous state. Acids feel sticky while bases have slippery consistency because they react with the oils of our hands. Taste of acids feels sour while that of bases feels bitter. The acid reacts with metals. Acids produce hydrogen gas after reaction while bases react with oils and fats. The strength of acids depends upon the concentration of hydrogen ions. The greater the concentration of hydrogen ions, the stronger is the acids. The strength of the bases is dependent upon the concentration of hydroxyl ions. The greater the concentration of hydroxyl ions, the stronger is the base.
Acids are positively charged due to the presence of positively charged hydrogen ions while bases have a negative charge upon them because of the presence of OH- ions in them. Acids show no color change with phenolphthalein while bases make it pink. The chemical formula of acids begins with H, (Hydrogen) for example HCL (hydrochloric acid), H2SO4 (Sulfuric acid). But this rule is not followed by acetic acid (CH3COOH), which chemical formula does not start with H. The chemical formula of bases ends at OH. For example sodium hydroxide (NaOH). Acids and bases also show a reaction with litmus. Acids change blue litmus paper to red while bases change red litmus paper to blue. Both acids and bases can conduct electricity because of the dissociation of free ions among them.
Acids are used for the cleaning of rusty metals, in fertilization production, as additives in foods and beverages, as electrolytes in batteries and in mineral processing. They are also used as preservatives, as carbonated drinks, in the leather industry and making sodas and flavors to foods etc.
Bases have the ability to remove stains, so they are used in dishwashing, detergents, laundry cleaners and oven cleaners. They are also used in medicines for stomach, i.e. antacids, in armpit deodorants and to neutralize acids.
Comparison chart
| Basis | Acid | Base |
| Arrhenius Concept | Acids are the compounds which have the ability to donate H+ ions when dissolved in water. | A base is a substance which is capable of donating OH- ions when dissolved in water. |
| Lowry Bronsted Concept | Acids have the ability to give protons to other substances. | Bases have the ability to accept protons from other substances. |
| Lewis Concept | The substances which are electrophiles, have a vacant orbital and have the ability to accept a pair of electrons are called Lewis acids. | The substances which are nucleophiles, have a lone pair of electrons and have the ability to donate a pair of electrons are called Lewis bases. |
| Reaction with water | When an acid is mixed with water, a solution is produced having a concentration of H+ ions greater than pure water. | When a base is mixed with water, a solution is produced having H+ concentration less than pure water. |
| pH range | Their pH ranges from 0 to less than 7. | Their pH varies from greater than 7 to 14. |
| Physical state | They may occur any of the physical states, i.e. liquids, solids or gases. | They occur in the solid state mostly except ammonia which is found in the gaseous state. |
| Reaction with litmus paper | They turn litmus paper to red. | They turn litmus paper to blue. |
| Reaction with phenolphthalein | They show no reaction with phenolphthalein. | They turn phenolphthalein to pink. |
| Chemical formula | The chemical formula of acids starts with H, e.g. HNO3 for Nitric acid, H2SO4 for sulfuric acid, HCL for hydrochloric acid. | Their chemical formula ends at OH, e.g. NaOH for sodium hydroxide, KOH for potassium hydroxide and Ca(OH)2 for calcium hydroxide. |
| Consistency | Acids are sticky on touch. They have a sour taste. | Bases are slippery on touch. They have a bitter taste. |
| Uses | Acids are used for the cleaning of rusty metals, as additives in foods and beverages, as electrolytes in batteries, in fertilizers and leather industries. | Bases are used in stain cleansers, arm pit deodorants, detergents, antacid medicines and to neutralize acids. |
What are acids?
The word ‘’acid’’ is derived from the Latin word “acere’’ which means sour. An acid is an ionic and corrosive substance which has the ability to give a hydrogen ion, accept a pair of electrons or donate a proton. The strength of an acid is measured by the concentration of H+ ions. A corrosive substance is that which damages or destroys other substances coming in contact with it. The greater the concentration of hydrogen ions, the stronger the acid is. Acidity is measured on the pH scale. It ranges from 0 to less than 7. The substances having the pH less are more acidic and vice versa.
Ionic compounds are those compounds which are charged either positive or negative. Acids are positively charged due to hydrogen ions.
Strong acids are those who completely dissociate into the water, e.g. HCL, HNO3 and H2SO4. Week acids are those who do not completely dissociate into the water, e.g. Acetic acid (CH3COOH).
Genetically important materials, i.e. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are also acids. Life is not possible without them. Vinegar is a commonly used household acid.
What are bases?
Bases are ionic and corrosive substances which have the ability to accept a hydrogen ion, give a pair of electrons or accept a proton from any other substance. The strength of bases is measured by the concentration of OH- ions. The greater the concentration of OH- ions, the stronger the base is. Bases range from greater than 7 to 14 on pH scale. High pH indicates the greater strength of the base. Bases are negatively charged due to the presence of OH- ions.
Strong bases are those bases which are completely dissociated into the water, e.g. NaOH, i.e. sodium hydroxide and KOH, i.e. potassium hydroxide.
Week bases are those who are not completely dissociated into the water, e.g. NH3, i.e. ammonia. It has not hydroxide ion and forms week base only on dissolving in water. Other examples of commonly used household bases are borax, baking soda and milk of magnesia (used as stomach medicine).
Key Differences between Acid and Base
The Key Differences between Acid and Base between Acid and Base are given below:
- Acids and bases both are corrosive substances. Acid has the ability to give a hydrogen ion or a proton or accept a pair of electron. Bases are capable of accepting a hydrogen ion or proton or give a pair of electron.
- Acids have a sour taste and sticky to touch. Bases have a bitter taste and slippery to touch.
- The chemical formula of acids starts with H, e.g. HCL, HNO3 while that of bases ends at OH, e.g. KOH, NaOH, etc.
- Acids turn litmus paper to red while bases turn it to blue.
- On pH scale, acids have a pH less than 7 while bases have a pH greater than 7.
Conclusion
Acids and basis have the basic importance in chemistry as well as in our day life. It is worthy to know about them. In the above article, we discussed the differences in acids and bases, their physical and chemical properties and three theories to understand their nature.