Question

What is the pH of a solution that has a $pOH$ of 9, is this solution acidic or basic?
A.9, basic
B.5, acidic
C.7, neutral
D.5, basic

Answer 1

The pH is defined as the potential of hydrogen which tells us about the concentration of hydrogen ions in the aqueous solution. It tells us whether the given solution is acidic or basic. The pH scale ranges from 0-14, pH less than 7 specifies acidity and pH greater than 7 specifies basicity, pH of 7 comes under neutral.
Formula Used: $pOH=14-pH$

Complete step by step answer:
The given $pOH$ of solution is 9. To find its pH value we will use the formula, $pOH=14-pH$.
So, pH = 14-9 = 5. On the pH scale variation from 0 to 7 comes under acidic. So the given solution is acidic in nature with pH value 5.

So, the correct choice is (B).

Additional Information: The pH value for a strong acid will be less than that for a weak acid which indicates that as the pH value approaches 7 the strength of acid keeps on decreasing. After crossing the value 7 the acidic character is lost and basicity comes into action. The pH scale is logarithmic due to which each whole pH value below 7 is ten times more acidic than the next higher value. The pH value can be measured using litmus paper. The pH value is significant as it reflects the chemical conditions of the solution. The human body also has different levels of pH for different body parts as our blood is slightly alkaline or basic with pH value between 7.35 and 7.45 whereas our stomach is quite acidic so that it can break down food for digestion.

Note:
The pH value 7 comes under neutral i.e. at this pH value there are equal no. of hydrogen and hydroxyl ions. . A solution of very strong acid will result in pH value 0 and similarly a solution of a very strong base will result in pH value 14. Remember that pH scale is logarithmic scale which means that the change in two consecutive values is not by a factor of 1.