The basic concept of acid, base and salt substances is extremely important in the chemistry study. We know that there are clear difference between acid, base and salt. They possess different chemical and physical properties. These qualities’ differences will lead to the different kind of reaction between acid, base and salt. This article will explain the difference between acid, base and salt including its basic concept and chemical reactions.
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1. Acid Concept & Reaction
We basically define acid as a substance which releases the ion of H+when it dissolves in the water. Acid contains the hydrogen element, like hydrochloric in HCL, nitric in HNO3, Sulphuric in H2S04 and so on. However, we also take a note that not all compounds having the hydrogen are acid. The example is H2O or water and CH4 or Methane. Here’re some popular examples of acid reaction when they dissolve in the water solution
H2SO4 → 2H+ + SO42
HNO3 → H+ + NO3–
HCl(g) → H+ (aq) + Cl- (aq)
The concept of above reaction was firstly discovered by Arrhenius. He produced the great theory about acid and base based on its chemical reaction in the water solution. There’re two types of acids consisting of organic and inorganic acid. The examples of inorganic acids are Nitric acid, sulphuric acid, hydrochloric acid. While the example of organic acid is the vinegar. The chemical formula of vinegar is CH3CO2H. However, we have to consider some acid reactions as the risky reaction like acid in water reaction. This reaction contains the risk of accident since the acid can strongly react with the water.
2. Base Concept & Reaction
While acid gives the H+ ion, base releases OH– the ion in the aqueous solution. The common form of base is metal hydroxide. The popular examples of base compound are Natrium Hydroxide (NaOH), Calcium Hydroxide (Ca(OH)2) and many more. Here’s an examples of base reaction when it dissolves i the aqueous solution:
NaOH(s) → Na+ (aq) + OH- (aq)
The solution of base in the water is often called as alkali. It has the properties of slippery.
3. Salt Concept & Reaction
When the acid and base react, they will form the new substance named salt. In this reaction, the ion of H+ and OH- will create water. The ion of non metal element of acid and ion of metal element of base will produce salt. So, the reaction of acid plus base will create salt plus water. Here’s some examples of acid and base reaction:
HCl + NaOH -> NaCl + H2O
H2SO4 + Ca(OH)2 -> CaSO4 + H2O
The ions in the salt substance will remain in the water solution. When there’s no water left, the salt will become crystal. However, there’re some salt which are not able to dissolve in the water. When acid reacts with base, the salt will precipitate. The popular example of this type of salt is as follow:
2HCl + Ba(OH)2 -> 2H2O + BaCl2
The barium chloride in the reaction above is in white precipitate form. There’s also another form of chemical reaction between acid and base to create salt. Salt can be produced by the reaction between the metal and acid. When metal dissolves in the acid solution, it will create the salt with hydrogen. The example of this reaction is as follow:
H2SO4 + Mg -> MgSO4 + H2
On the reaction above, we can see that magnesium can dissolve in the sulphuric acid to form the magnesium sulphate and hydrogen. The reaction of metal in the acid solution is not only able to produce salt + hydrogen, but also create salt + water + carbon dioxide. This kind of reaction usually occurs in the metal carbonate element which has the unstable properties. Here’s the example of this reaction:
2HCl + CaCO3 —-> CaCl2 + H2O + CO2
We can see that the Calcium carbonate can dissolve in the hydrochloric acid solution to create CaCl2 plus water plus carbon dioxide. Thus, there are the basic differences between acid, base and salt.
Salt also has special reaction with the metal. If we react the metal with the salt of another metal, it will produce the salt of first metal and second metal. Its reaction can be described below:
Metal 1 + Salt of Metal 2 -> Salt of Metal 1 + Metal 2
This reaction is called displacement reaction. This reaction will occur if the salt of metal which react with first metal is the less reactive metal. Let see the example of this displacement reaction:
Fe + CuSO4 —-> FeSO4 + Cu
In the reaction above, iron (fe) reacts with the salt of copper (CuS04). They will produce the salt of iron (FeS04) and copper (Cu). This displacement reaction can occur because the copper is less reactive than iron. In this reaction, the solution will change its color to green since it produces the iron sulphate. While the copper will remain as the red powder. To understand this reaction, we have to fully understand about the metal reactivity table.
This table will tell us the metal which is most reactive and the one which is least reactive. Based on the its properties, the most un-reactive metal is gold. It means that gold can not dissolve in the acid solution. Acid is not able to attack gold. While the most reactive metal are potassium, calcium and sodium. Since they’re strongly reactive, water can attack these metal.
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Difference between Acid, Base and Salt
We can see some difference between acid, base and salt from some different perspectives. It can be its properties, chemical reaction, chemical containment and so on. Here’re some points which can differ the acid, base and salt substances.
1. Definition by Arrhenius
As we mentioned previously, Arrhenius is the great scientist who conducted the study about acid and base substance. His discovery gave the vital contribution in the world of chemistry, especially in the Branches of Organic Chemistry. Based on his theory, he’s able to explain the difference between acid, base and salt. He said that acid will produce the H+ ion in the water solution. The level of H+ ion released by acid will be greater than the pure water. While base will produce ion of OH- in the water solution.
2. Bronstead-Lowry Theory
Bronstead-Lowry is another great chemist who successfully discovered the theory about acid and base. Using the previous theory from Arrhenius, they made the theory with the base of proton activities. He concluded that acid will produce proton, while base will accept the proton. This theory is relevant in the water solution. Bronstead-Lowry calls acid as the proton donor, while base as the proton acceptor.
3. pH Level
pH level is another thing that we can find as the difference between acid, base and salt. The pH level actually describes the level of positive hydrogen ions and negative hydroxide ions in the solution. We know the pH level as the potential hydrogen level. Scientists use the pH level to measure the level of acidity or alkalinity in the solution. Acid has the lower pH, while base has the higher pH.
The value of acid pH is less than 7, while the base pH values is greater than 7. pH value of 7 is the neutral pH value. We can understand that the higher level of positive hydrogen ions in the solution, pH will become less. In contrast, the high level of negative hydroxide in the solution will make the pH greater.
Salt is the product of acid and base reaction. In this reaction, both acid and base neutralizes each other so that the product of their reaction will contain neutral substance like salt. In this reaction, base’s negative ions and acid will form the water, while the positive ions will create the salt.
4. Litmus Paper & Phenolphthalein
We can also see the difference between acid, base and salt by conducting the chemical experiment. We must have learned the basic experiment in the school laboratory about litmus paper. This is the tool to determine the properties of substance. This paper can also check whether the substance acid or base. If it’s acid, it will turn the blue litmus paper to the red color.
In contrary, base substance will change the red colored litmus paper to the blue colored litmus paper. We can also use the phenolphthalein to check the type of substance. It’s the chemical compound which is used as the pH indicator. We simply and add this compound to both acid and base solution to see their reaction. The acid will remain colorless with the addition of this compound. While the base solution will turn into pink colored solution after this phenolphthalein addition.
5. Chemical Formula
Different substances must have different kind of properties and formula. The formula of acid, base and salt should be different than each others. The acid usually has the H formula in the beginning of its chemical formula. We can see this example on HCl, H2S04, HNO3 and many more. You can see their chemical reactions on the above section. However, not all acids contain H letter on the beginning of their chemical formula. There’s substance which has no H formula in its beginning formula. It’s vinegar or CH3COOH. It’s still considered as acid solution even though it has no H in its formula’s first letter.
If acid has H letter on the beginning, base has the OH formula on the end of its chemical formula. in the sodium hydroxide or NaOH, there’s OH on the end of its formula. Indeed, that’s the differences between acid, base and salt in chemicals compound and reactions.
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