Acidic, Basic, or Neutral pH of NaCl

The chemical formula for sodium chloride, widely known as table salt or common salt, is NaCl. It’s an ionic molecule with a molecular mass of 58.44 g/mol that’s made up of sodium (Na+) and chloride (Cl-) ions in a 1:1 ratio.

The sodium chloride content of saltwater is roughly 2.7-2.9 percent, which is the main reason for its saline quality. In its pure form, NaCl appears to be a white crystalline solid that dissolves to a colourless solution in water.

Let’s start with our article on NaCl’s ph and what nature it has, such as acidic, basic, or neutral.

What is the ph of NaCl, then? Because it has a pH of 7, NaCl is a neutral chemical. It has neither an acidic nor a basic pH. Because it is created by the neutralisation reaction between HCl (strong acid) and NaOH, NaCl is neutral (strong base). In an aqueous solution, a strong acid and a strong base neutralise each other, yielding a neutral result, such as NaCl with a ph value of 7.

Let’s take a closer look at the explanation behind this in the following context.

Why is NaCl considered neutral?

Lewis Structure of NaCl

The neutrality of sodium chloride is based on the assumption that a compound’s acidic, basic, or neutral nature can be easily determined by its pH value.

Any compound with a pH value less than 7 is acidic, whereas those with a pH value more than 7 are basic or alkaline, and those with a pH value equal to 7 are neutral.

NaCl is considered neutral in nature because it has a pH value of 7.

When an acid reacts with a base, a salt is formed that combines the properties of both the acid and the base.

NaCl is the result of a reaction between a strong basic, NaOH, and a strong acid, HCl.

Because it contains an equal number of hydrogen and hydroxyl ions, it dissolves in water to produce a colourless neutral solution.

Why does NaCl have neither an acidic nor a basic pH?

Acids produce hydrogen ions when dissolved in water, which mix with water molecules to form hydronium ions, whereas bases absorb these hydrogen ions to form hydroxide ions.

Any acid-base reaction requires this ion exchange to take place.

When NaCl is dissolved in water, however, it simply creates sodium and chloride ions, therefore no such exchange occurs.

These sodium (Na+) and chloride (Cl-) ions are weak conjugate acids and bases, respectively, and hence do not have enough intensity to cause the solution to become acidic or basic.

These ions also work together to create a neutral salt solution.

Calculating the pH of NaCl

The pH of solid NaCl can be easily measured by dissolving it in modest amounts of water.

It creates sodium ions (Na+) and chloride ions when entirely dissolved (Cl-).

The following equation represents this dissociation:

NaCl(s)   —->  Na+(aq)   +   Cl-(aq)

The water molecules do not react with the sodium or chloride ions.

Because sodium ions combine with water molecules to form sodium hydroxide, a strong base, the sodium ions eventually dissociate back into sodium ions.

This is exemplified by the following two reactions:

Na+(aq)   +   H2O(l)   ⇋   NaOH(aq)   +   H+(aq)

NaOH(aq)   →   Na+(aq) + OH-(aq)

Similarly, when chloride ions combine with water to generate hydrochloric acid, a powerful acid, it dissociates back into chloride ions, as shown in the following two equations;

Cl-(aq)  +  H2O(l)   ⇋   HCl(aq)  + OH-(aq)

HCl(aq)   —–>   H+(aq) + Cl-(aq)

When a strong acid and a strong base, such as sodium chloride, are dissolved in water, the conjugate acid and base do not contribute to the pH of the final solution.

The only ions that contribute to the final pH value are the hydrogen and hydroxide ions, which are dissociated by water.

The chemical equation for auto-ionization of water is as follows:

H2O(l)   ⇋   H+(aq)   +   OH-(aq)

For this equation, the ionic product of water (Kw) would be something like

Kw = [H+(aq)][OH-(aq)]

In the case of water, we know that the hydrogen ion concentration is equal to the hydroxide ion concentration, i.e. [H+(aq)] =[OH-(aq)].

As a result, the ionic product equation would be formatted as;

[H+(aq)] = Kw

2

This gives us the concentration of hydrogen ions, which is equal to the square root of water’s ionic product.

Because Kw = 10-14 at 25°C, the hydrogen ion concentration will be 10-7 mol L-1.

pH = −log10[H+(aq)]

pH = −log10[10-7] = 7

The negative of the log of hydrogen ion concentration is now used to compute pH. This will then provide us with the

pH as follows:

pH = −log10[H+(aq)]

pH = −log10[10-7] = 7

As a result of the calculations, it can be determined that the pH of sodium chloride when dissolved in water at room temperature (25°C) is 7.

NaCl’s structure

Because NaCl is an inorganic chemical, the rules used to comprehend the structures of organic compounds do not apply to it.

The crystal structure of NaCl is a rock salt with a face-centered cubic Bravais lattice.

It is made by repeating face-centered cubic unit cells with a 1:1 ratio of Na+ and Cl-ions in each unit cell.

The 1:1 ratio denotes that the number of Na+ cations matches the number of Cl- anions.

In the CCP kind of arrangement, the chloride ions are present inside the lattice, which means they are at the cube’s corners and face centres.

The sodium ions are present in such a way that they are surrounded by six chloride ions, or we can say that they occupy all of the octahedral gaps.

Each chloride anion has six sodium cations surrounding it, and vice versa, forming what seems to be a regular octahedron in the diagram.

This also means that the cations and anions in the structure have a 6:6 coordination ratio, and that each unit cell includes four cations and four anions, for a total of eight ions in one unit cell.

The Lattice constant (a) of 0.564nm and the lattice parameters: 1) sides (a=b=c) and 2) angles (=90,=90,=90) are all included in a single unit call.

You should read the post I wrote about whether NaCl is ionic or covalent.

Properties

The density of sodium chloride is 2.16 g/mL, with a boiling point of 1465°C and a melting point of 801°C.

It doesn’t have a distinct fragrance, but it does have a distinct flavour.

It is entirely soluble in water and other polar solvents, but only slightly soluble or insoluble in most other liquids.

The aqueous solution it produces is known as saline solution, and it comes in a variety of concentrations.

It decomposes at a high temperature range, emitting hazardous fumes of hydrochloric acid (HCl) and disodium oxide (Na2O) as it does so.

Because of the unrestricted movement of the ions in the solution, it is known to be a good conductor of electricity in the aqueous state.

Uses

Sodium chloride is used in a variety of industries, including the following:

It’s commonly used as a food preservative as well as a flavour enhancer.

It is an important raw material that is used in the production of chemical products such as sodium carbonate (Na2CO3), sodium hydrogen carbonate (NaHCO3), baking soda, hydrochloric acid, and glass.

It is used to prevent the accumulation of snow on road tracks, bridges, railway tracks, and other surfaces in nations where snowfall occurs every year during the winter season, which is required for safe driving and walking.

It is a common industrial substance found in oil refineries, textiles, fire retardants, rubber, and other sectors.

It is necessary for the human body to maintain its electrolyte balance in its fluids. Dehydration or overhydration can occur if the levels fall too low or rise too high.

NaCl plays a variety of roles in the human body, including nutrient transportation and absorption, hydration, and blood pressure regulation, among others.

Conclusion

To summarise, we are all familiar with NaCl because we use salt on a daily basis to flavour our meals. It has a rock salt structure, as previously mentioned.

When dissolved in water, it appears to be a white crystalline solid that forms a colourless solution. It is a pH scale of 7 and is a neutral chemical.

It is formed when sodium hydroxide and hydrochloric acid combine. It has a wide range of industrial and health-care applications, some of which were reviewed in this context.

We have a comparable article on KCl, which is a related salt. Determine whether KCl is ionic or covalent.

Good luck with your studies!!

Read more: Lewis Structure, Molecular Geometry, Hybridization, and Polarity of Magnesium Chloride

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.

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