What is the difference between $ pH $ and hydrogen ion concentration?

Hint: Hydrogen is an atom and it turns into an ion known as hydrogen ion with the symbol of $ {H^ + } $ . The number of moles of $ {H^ + } $ in one litre of solution will be known as hydrogen ion concentration. Whereas $ pH $ is defined as the negative logarithm of the $ {H^ + } $ ion concentration.

Complete Step By Step Answer:
Hydrogen is a chemical element with atomic number $ 1 $ and has only one electron in its shell. This one electron can also be removed easily and the hydrogen atom can turn into hydrogen ion which can be represented as $ {H^ + } $
Concentration is the factor or quantity that talks about the amount of substance present in the particular volume of solution. Hydrogen ion concentration is defined as the number of moles present in one litre of solution. As the concentration can be written in the terms of number of moles and volume of solution in litres.
 $ pH $ is defined as the negative logarithm of the $ {H^ + } $ ion concentration. The relation between the terms $ pH $ and $ {H^ + } $ can be written as:
 $ pH = - \log \left( {{H^ + }} \right) $
The pH of chemical compounds generally varies from $ 1 $ to $ 14 $ . It can be measured in pH scale which was introduced by Sorensen. It represents the acidity and basicity of the chemical compounds. The value of $ pH $ can be calculated from the hydrogen ion concentration by substituting in the above equation.

Note:
The value of $ pH $ from $ 1 $ to below $ 7 $ represents the acidic nature. The value of $ pH $ from above $ 7 $ to $ 14 $ represents the acidic nature. The value of $ pH $ $ 7 $ represents neutral compounds like water. Water has a pH of $ 7 $ .