Acids bases salts and pH level.
Acids, bases and salts are inorganic substances that break up
or dissociate in solution, or water, to form charged particles or ions.
The positive ions are called cations, and the
negatively charged ions are called anions.
Before we look at acids, bases and salts, let’s take a look at water.
A water molecule is made up of an oxygen atom and two hydrogen atoms
that are covalently bonded, or share electrons with the oxygen atom.
However, the electrons are not shared equally within the molecule,
as they have a higher probability of being found closer to the nucleus
of the oxygen atom, giving that end a slightly negative charge.
So, the hydrogen atoms end of the molecule will have a slightly positive charge.
These charged ends weakly attach the positive end of one water
molecule to the negative end of an adjacent water molecule.
This is attraction or bonding is called a hydrogen bond.
Sometimes this attraction of a hydrogen atom of one water molecule
to another molecule becomes so strong that it actually detaches from
its original molecule and attaches to the other water molecule.
So this yields a hydronium or H3O positive ion, and a hydroxide or OH negative ion.
Also, water molecules continually dissociate to form
positive hydrogen ions and negative hydroxide ions;
this is a reversible reaction as noted by the formula H2O double arrow,
or reversible reaction, positive hydrogen ion and negative hydroxide ion.
The actual amount of these positive H3O or hydrogen
ions in water is actually very very small.
To make things easier to understand we will consider the positive H3O ion
and the positive hydrogen ion as one in the same.
So, in pure water, the amount of positive
hydrogen ions and negative OH ions is the same.
Now for acids.
An acid is any substance that when added to an aqueous solution, or water,
will release a hydrogen ion or increase the concentration of hydrogen ions.
So, how strong an acid is depends on the amount of hydrogen ions produced.
For instance hydrochloric acid or HCl, which
is a hydrogen atom bonded to a chlorine atom,
when added to solution or water will dissociate or break
down into negative chlorine ions and positive hydrogen ions.
Hydrochloric acid is a strong acid, as it completely dissociates in water.
Now for bases.
Bases are essentially the opposites of acids, in that they shift the
hydrogen ion, hydroxide ion balance in favor of the negative hydroxide ion.
This can be done by increasing the number of hydroxide
ions, or decreasing the number of hydrogen ions.
For instance, sodium hydroxide or NaOH, will break down,
or dissociate into positive Na ions and negative OH ions.
So, the balance has shifted in favor of the negative
hydroxide ions, meaning sodium hydroxide is a base.
Bases can also be strong or weak depending on how well
they break apart, sodium hydroxide is a strong base.
This brings us next to the pH scale, which is basically
an abbreviation for the phrase “power of hydrogen”.
So, the ph scale measures the concentration of hydrogen ions of a solution,
or it measures how acidic or basic a substance is.
As the amount of positive hydrogen ions increases, the
pH goes down, and the solution becomes more acidic.
As the amount of positive hydrogen ions decreases,
the pH goes up, and the solution becomes more basic.
On a pH scale, a pH of 7 means the solution is neutral,
or the number of positive hydrogen ions equals
the number of negative hydroxide or OH ions.
A pH of less than 7 means the solution is more
acidic or more hydrogen ions than hydroxide ions,
and a pH of greater than 7 means the solution is more
basic, or more hydroxide ions than hydrogen ions.
On the scale, hydrochloric acid, which we mentioned earlier, and is
produced in the stomach, is at the most acidic end having a pH of zero,
vinegar has a pH of 3, coffee has a pH of 5,
and pure water has pH of 7, making it neutral.
On the opposite end, sodium hydroxide, which we mentioned
earlier, is at the most basic or alkaline end having a pH of 14,
ammonia has a pH of about 11, and baking soda has a pH of between 8 and 9.
Now we can look at salts.
A salt is a chemical compound formed from the reaction of an acid with a base.
So, hydrochloric acid, HCl can interact with sodium hydroxide
NaOH, a base, and form sodium chloride NaCl and water H2O.
Salts break apart, or dissociate in a solution
of water to from positive and negative ions,
which make them important for certain body functions.
There are many different salts that are important in the body
such as sodium chloride or NaCl and potassium chloride or KCl.
These salts are often most effective as charged ions or atoms in solution,
as a positively charged potassium ion and the positively
charged sodium ion are required for muscle contraction.
And that, be the basics on acids, bases, salts and pH level.