Question

The pH of decimolar solution of KOH is
(A) 1
(B) 4
(C) 10
(D) 13

Answer 1

Hint: The pH scale determines how acidic or basic water is. The range is 0 to 14, with 7 representing neutrality. Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7. In reality, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water.

Complete Step by Step Solution:
While water with more free hydroxyl ions is basic, water with more free hydrogen ions is acidic. Since chemicals in the water can change pH, pH is a crucial sign that the chemical composition of the water is changing. "Logarithmic units" are used to report pH. Each number corresponds to a 10-fold difference in the water's acidity or basicity. Ten times more acidic is water with a pH of five than is water with a pH of six.

Strong bases, such as KOH, separate into their constituent ions when dissolved in water. Although potassium hydroxide (KOH) has an exceptionally high pH (normal solutions typically range from 10 to 13), the precise value depends on how much of this powerful base is present in the water.

A decimolar solution has a molarity of 1/10 M for KOH.
So let's start by locating the p[OH]:
$p[O H]=-\log _{10}(O H) \\$
$\Longrightarrow p[O H]=-\log _{10} 10^{-1} \\$
$\Longrightarrow p[O H]=-(-1) \\$
$\Longrightarrow p[O H]=1$

Now, we know that $\mathrm{p}[\mathrm{H}]+\mathrm{p}[\mathrm{OH}]=14$ :
$\Longrightarrow p[H]=14-p[O H] \\$
$\Longrightarrow p[H]=14-1 \\$
$\Longrightarrow p[H]=13$

$So, pH of KOH solution is $13 .$
Hence the ph of the solution is 13.

Note: Potassium hydroxide, sometimes known as caustic potash, is an inorganic chemical with the formula KOH.KOH is a typical strong base, along with sodium hydroxide. It has numerous industrial and specialised uses, the majority of which make use of its caustic properties and acid reactivity. In 2005, a production of 700,000 to 800,000 tonnes was anticipated. KOH is notable since it is the source of many potassium-containing compounds as well as the majority of soft and liquid soaps. It is a potentially corrosive white solid.