Is NaCl an Acid or Base or Neutral? [Overview with pH of NaCl]

The present article is about Is NaCl acid or base?

Before going towards whether the NaCl is acid and base we have to go through some important points which makes us easy to determine is NaCL acid, base and salt?

How it is formed structurally?

NaCl is one of the most popular and usable inorganic compound on earth. It is ionic compound and soluble in water.  Most of the bond form between metal ion and non-metal ion are ionic. Sodium chloride is formed by the bondinhg between metal ion (Na+) and non-metal ion (Cl). Hence it is it kept under ionic compound. The electronegativity difference between sodium and chlorine atom is 2.0 (the number may vary according to reference we used).

The compound in which electronegativity difference between atoms is greater than 1.7 the compound is ionic compound. In ionic compound complete transfer of electron from one atom to another atom takes place making one atom fully positively charge and another atom fully negatively charge. So in case of sodium hydroxide complete transfer of electron takes place from sodium to chlorine atom making sodium completely positively charged and chlorine negatively charged. Here both element maintain stability following octet rules as given below in atomic structure.

Complete transfer of electron making two oppositely charged ion.

In this way sodium chloride is the 1:1 combination of sodium and chlorine ion.

Is sodium chloride acid or base? Is the main topic of our study so let’s move to this point.

Is NaCl acid or base?

Commonly it is called salt i.e. neither acid nor base.

What makes sodium chloride salt?

There are many factor which makes the sodium chloride base they are,

pH value; the pH value of sodium chloride is 7 i.e neutral salt. It is formed by the neutralization reaction between strong acid (HCl) and strong base (NaOH).

Which type of salt is sodium chloride?

Basically there are three type of salt they are

Acidic salt; the salt which make solution acidic when dissolve in water is called acidic salt. For example ammonium chloride (NH4Cl). When this salt dissolve in water the concentration of H+ ion is higher than concentration of hydroxyl ion in solution. Hence the solution becomes acidic.

Basic salt; the salt which makes the solution basic when dissolved in water is called basic solution. For example CaCO3. When this salt dissolve in solution it makes the pH of the solution greater than 7.

Neutral salt; the salt which make the solution neutral when dissolve in water. For example NaCl when these salt dissolve in water they make the pH of solution equal to 7.

Hence, NaCl is neutral salt.

What makes the sodium chloride neutral salt?

Its pH value has great role to make NaCl neutral.

And it is also according to the following concept of neutralization reaction.

Neutralization reaction between strong acid and weak base form acidic salt.

For example, ammonium chloride (NH4Cl) is acidic salt form by the neutralization reaction between strong acid (HCl) and weak base (NH4OH). pH value of acidic salt is less than 7.but the value of sodium chloride is 7.

Neutralization reaction between strong base and strong acid forms basic salt. For example, sodium acetate (NaOOCCH3), is basic salt formed by the neutralization reaction between strong base NaOH and weak acid CH3COOH. pH value of basic salt is between (8-14). This value also does not match with the value of sodium chloride.

Neutralization reaction between strong acid and strong base forms neutral salt. For example, sodium chloride (NaCl) is formed by the neutralization reaction between strong acid (HCl) and strong base (NaOH). Hence, the sodium chloride is neutral salt.

Both Na+ and Cl are weak because they are conjugate acid and conjugate base formed from strong base and strong acid respectively. So they both do not go hydrolysis on aqueous solution and make the solution neutral.

Why sodium chloride is not acid and base?

To understand whether the given compound is acid or base or why not both we have to understand three broad concept of acid and base.

Arrhenius concept of acid and base; according to this concept acid are those compound which furnishes the hydrogen ion in in aqueous solution for example

HCl (aq)     →       H (aq) +Cl (aq) hence, HCl is Arrhenius acid. Other example are HBr, H2S and so on.  Similarly, base are those compound which furnishes the hydroxide ion in solution. For example sodium hydroxide.

NaOH (aq)      →            Na+ (aq) + OH (aq)      

But sodium chloride do not furnishes the hydrogen ion in solution. In aqueous medium it is dissociates into sodium and chloride ion.  So, sodium chloride is not Arrhenius acid and base.

Brosted-Lowry acid base concept; in his theory also depends on proton theory. Acording to this concept acid are those substances which gives up proton to any other.  And base are those compound which accept proton and have at least one pair of electron to accept proton For example

: NH3 + HCl            →                NH4+ + Cl

Bronsted-Lowry base                       conjugate acid


Bronsted-Lowry acid            conjugate base

Other example of acid are HNO3, H2SO4 and base are water and case of NaCl neither it has lone pair to accept proton nor it gives proton to other. Hence, sodium chloride is not Bronsted-Lowry acid and base.

Lewis theory of acid and base; this theory gives different concept than other two theories because Lewis acid base concept does not depends on transfer of proton. According to this concept acid are those species which has empty orbital to accept pair of electron from other for example H+,  K+. And base are those species which has filled orbital with lone pair of electron for example ammonia (NH3) and Br2. But sodium chloride do not follow this rule too.

Hence sodium chloride is not acid and base.

To be acid compound should have pH value less than 7 and to be base the value must be (8-14) but pH value of NaCl does not match any of them. So it is neither acid nor base. Instead it has the pH value of 7 which indicate it is neutral salt.

Litmus test; the compound to be acid must change the blue litmus into red and the base change it from red to blue. But sodium chloride remains neutral, it does not change the colour of litmus paper.

Formation of sodium chloride; it is the significant constituent of sea water so it can be obtain by evaporating of sea water.  We can obtain pure salt by using mineral halite. It can also take out from brine and salt lakes. Salt can be obtained as the by- product of the potassium mining.

In lab it is prepare by combining sodium metal and chlorine.

2Na(s)+ Cl2(g) →2NaCl(s)

Properties of sodium chloride

Sodium chloride is highly soluble in water but less soluble in other compound. Because attraction between Na+ and Cl is very strong so, only very polar solvent like water dissolve it perfectly.

It is white crystal found in nature.

It involve 1:1 ratio of sodium and chlorine during the formation.

In high temperature it becomes poisonous because it produce toxic fumes of Na2O and HCl by decomposition.

It is the main constituent of sea water.

It may be dangerous at high concentration however, at low concentration it is nontoxic and useable.

Boiling point and melting point of sodium chloride is 1,465 °C and 800.7 °C respectively.

In water it is highly soluble and dissociates into its ions so it is good electrolytes i.e. conduct electricity.

The electronegativity difference between its constituent ions makes it ionic.

It is responsible for the salinity of sea water.

Sodium chloride lack any odour but have very sensitive taste.

Molar mass of sodium chloride is 58.44 g/mol.

100 g of NaCl contains 39.34 g Na and 60.66 g Cl.

Specific gravity of sodium chloride is 2.165.

Crystal structure of sodium chloride

 NaCl contain equal number of two opposite ion. They are located at the alternate position of the cubic lattice. In which each ion are surrounded by six other ions. This type of structure belongs to face centred cubic lattice. In which sodium ion occupies the space of lattice point and chloride ion is pointed at between the lattice points, as given below.

Some reaction of sodium chloride

Precipitation reaction; aqueous sodium chloride undergo the precipitation reaction with aqueous silver nitrate silver nitrate. It require high concentration of both compound.

AgNO3(aq) + NaCl(aq)     →       AgCl(s) + NaNO3(aq)

White precipitate

When electic current is passed to molten sodium chloride sodium and chlorine gas is obtained

NaCl(molten)                    →                        Na   +  Cl2(g)

In this reaction sodium is deposited at negative electrode and chlorine gas is deposited at positive electrode.

When current is passed to concentrated sodium chloride solution in water three component are separated

Chlorine (Cl2), Sodium hydroxide (NaOH), Hydrogen (H2). Here, mixture of hydrogen and chlorine may be explosive so they should be kept separately. All three product may combine to form other product which can also be used.

Sodium chloride react with fluorine gas where fluorine replace the chlorine

2NaCl(s)  +F2(g)         →          NaF(s) +Cl2(g)

Uses of sodium chloride

The major application of sodium chloride is de-icing of road way during the very cold weather.

It is used as the condiment and preservative in food industries

Sodium chloride is used in the production of many chemicals

It is used in the clor- alkali industry for chlor-alkali process i.e. the process of formation of sodium hydroxide by electrolysis process.

2 NaCl + 2 H2O → Cl2 + H2 + 2 NaOH

It is used for solvey process in the soda-ash industry to produce sodium carbonate and calcium chloride.

It is also used for the production of sodium sulphate and hydrochloric acid.

Sodium chloride is used to generate the ion-exchange resin which is used to soften the hard water.

It is also use as desiccant due to its hygroscopic nature.

It is used in textile and dyes because salt include positively charged ion which can promote the absorption of negative charge of dyes.

It is used to process some metals. As well as used in paper industry.

It is used in oil and gas exploration.

It is also use in medicine like nasal solution and intravenous therapy i.e. technique to deliver fluid directly to nerve. It is used in the fire extinguisher.

It is also used in some brand of shampoo.

Effect of sodium chloride; it is associated with gradually destruction of material like bridge decks, motor vehicles, reinforcement bar and wire, and unprotected steel structures used in road construction by chemical and electrochemical reaction with environment.  So, Airlines utilize more glycol and sugar rather than salt based solutions for removing ice.


From above study it is concluded that sodium chloride is ionic neutral salt involve 1:1 ratio of sodium and chloride ion. Commonly, it is called common salt and table salt. It belong to face centred cubic form of crystal.  Sodium chloride is neither acid nor base because it does not follow three broad concept of acid and base they are Arrhenius acid base concept, Bronsted-Lowry acid base concept and Lewis acid base concept. pH value of sodium chloride is 7 which  also play vital role to make it neutral.

Another important point to be noted is sodium chloride is result of neutralization reaction of strong base and strong acid which form conjugate  acid and base pair Na+ and Cl+ respectively and they are too weak to get  hydrolysis in aqueous solution mean that they do not go under hydrolysis reaction. They both do not affect the pH value of solution. Hence, sodium chloride is kept as a neutral salt.  The neutrality of sodium chloride is determined by litmus test also. It is highly soluble in water. It is very useful and use in many industries as well as in our day to day life. Its main uses is de-icing. Despite this, it is corrosive too. It is also used for synthesising other chemical compounds.  The units which are separated by passing current to sodium chloride they can recombine to make further product.



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