Question

A measure of hydrogen ion concentration is:
A. pH
B. pOH
C. \[{{\text{K}}_{\text{a}}}\]
D. conjugate acid

Answer 1

Hint: For this problem, we have to study each part that is given in the question so that we can determine the correct parameter which helps in measuring the hydrogen ion concentration.

Complete step by step answer:
- In the given question, we have to explain the correct parameter which helps in determining the concentration of the hydrogen ion in the solution.
- As we know that pH is defined as the power of hydrogen which is also equal to the negative logarithm of the concentration of the hydrogen ion.
- The pH of the solution is calculated by the expression that is: $\text{pH = -log}{{\text{H}}^{+}}$.
- Moreover, when we have to determine whether the solution is acidic or basic, we use the litmus paper and then compare it with the pH scale.
- Because the colour of the litmus paper describes the nature of the solution.
- If the value of the Ph scale comes to between 1-6 it is considered as acidic.
- Whereas if the value of the litmus paper is between 7 - 14 it is considered as the basic solution.
- And to calculate the basic nature of the solution we use the term pOH which is equal to the negative of logarithm of the hydroxyl ion as shown:
$\text{pOH = -logO}{{\text{H}}^{-}}$
So, the correct answer is “Option A”.

Note: In the problem, \[{{\text{K}}_{\text{a}}}\] is known as the acid dissociation constant which is used to determine the strength of the acid with which it can dissociate to give its respective ions but not the concentration of hydrogen ion. Whereas conjugate acid is those species which can donate hydrogen ions easily.