Different Types of Salts
One must have tasted a piece of Lemon or Orange and it feels sour. Do you know why an orange or lemon tastes sour?
Orange and lemon are sour in taste because of the presence of acids in them.
Have you tasted mustard seeds used for cooking food? Mustard seeds contain some basic compounds and impart bitter taste to them.
Overall the acidic and basic compounds are part of our everyday life.
Acidic compounds could be identified by their sour taste while basic compounds are bitter in taste. There are several examples around us including our daily food which contains some or the other acidic and basic chemical substances.
Some common examples are citric acid which are found in citrus fruits such as oranges and lemons, while acetic acid found in vinegar, and tartaric acids in tamarind etc.
We can observe many acidic chemical substances in the laboratory as well such as Hydrochloric acid (HCl), Sulphuric acid (H2SO4), Nitric acid (HNO3) and Phosphoric acid (H3PO4) etc.
Generally basic compounds are soluble in water and the aqueous solution of bases is called as alkalis.
There are several household items in which basic chemical substances are present as major ingredients such as dish wash liquid, Ammonia solution, toothpaste, cleaner and soap etc.
Many living bodies including human body also contains some kinds of acids and bases.
A very common acid is the dilute Hydrochloric acid present in our stomach, which involves in the digestion process of food materials in stomach.
Urine, blood, and intestinal fluid are alkaline in nature.
The reaction of an acid and a bases yields two products; water and an ionic compound known as salt.
This kind of reaction is called a neutralization reaction. It is an exothermic reaction which liberates some amount of heat that remains constant for any of the acid and base.
This heat is known as heat of neutralization which is around 57.7 kJ per mole of H+ ion.
Salts are ionic compounds whose nature depends upon the nature of acid and base involve in the reaction.
For example; Sodium Chloride or table salt is produced from the neutralization reaction of Sodium Hydroxide (base) and Hydrochloric acid.
Other examples of salts are Epsom salts (MgSO4) used in bath salts, Ammonium Nitrate (NH4NO3) used as a fertilizer and Baking Soda (NaHCO3) used in cooking.
The chemical formula of salt derives from the formula of constituent acid and base. The positive ion of the salt comes from an acid while the negative part will come from the base.
Salts are formed due to the combination of an anion and a cation from the base and acid respectively; and therefore the pH of the salt solution completely depends on the constituent acid and base from which the salt is formed.
For instance Sodium Chloride which is a neutral compound but baking soda that is Sodium Hydrogen Carbonate (NaHCO3) forms an alkaline aqueous solution.
Sodium bi-Carbonate is also known as the baking soda, and is manufactured by the Solvay process, in which Sodium Carbonate is formed as an intermediate.
On heating, baking soda decomposes to Carbon dioxide gas as given in the following reaction:
2NaHCO3 --> Na2CO3 + H2O + CO2
Another salt of sodium is Sodium Carbonate or soda (Na2CO3) which infact was known to people even in ancient times. It is now used for the manufacturing of glass when combined with Calcium Oxide.
It could exist in several forms like anhydrous, mono-hydrate, hepta-hydrate and deca-hydrate forms.
This is made by the Ammonia-Soda process or Solvay process in which Sodium Chloride, Ammonia and Limestone act as the raw materials.
It is widely used in the water purification and sewage treatment systems.
Another example of salt is the bleaching powder Calcium Hypochlorite Ca(OCl)2.
The bleaching powder is also known as Calcium Oxy-Chloride and the formula is Ca(OCl)2 which can be prepared reacting slaked lime
[Ca (OH)2] and Chlorine gas (Cl2).