Question

The pH value increases with:
(A) Increase in hydrogen ion concentration
(B) Decrease in hydrogen ion concentration
(C) No change in hydrogen ion concentration
(D) None of the above

Answer 1

If we translate the meaning of pH it literally means the power of Hydrogen or potential of Hydrogen. pH represented the ability of an acid or base to dissociate into hydrogen ions and hydroxide ions respectively in their aqueous solution.

Complete answer:
$pH$ is used to determine the acidity or basicity of an aqueous solution. It indicates the concentration of ${H^ + }$ or $O{H^ - }$ions in the solution. It is calculated using the logarithmic of the Hydrogen ion concentration in the solution. It given as $pH = - log{{ }}\left[ {concentration{{ }}of{{ }}{H^ + }} \right]$.pH helps us determining the acidity and basicity of a solution. With the help of pH, you can also determine the strength of an acid or base. The pH scale is a tool for the measurement of pH, with the help of pH scale we can easily determine whether a given molecule is an acid or base. The pH scale has value ranging from $0 - 14$. The indicator that we used is litmus paper. If the value on scale lies in the range of $0 - 7$, then those solutions are termed as ACIDIC and if the value lies in the range of $7 - 14$, then those solutions are termed as BASIC. A higher pH value means the concentration of ${H^ + }$ is low or you can say that the concentration of $O{H^ - }$ ion is high. If the pH value is low then you can say that the concentration of ${H^ + }$ is high. The concentration of $O{H^ - }$ ion is low. Hence we can say that on decreasing the concentration of hydrogen ion pH value increases.

Therefore, option (B) is correct.

Note:
The pH value for strong acid or strong base is independent of the temperature. The pH value of weak acid decreases with temperature because of the increase in the ionization and for a weak base, it increases with ionization.