Question

The ionization constant of water is \[1.1\times {{10}^{-16}}.\] What is the ionic product of water?
A.\[1.1\times {{10}^{-16}}\times 6.023\times {{10}^{23}}\]
B.\[\dfrac{1.1\times {{10}^{-16}}}{0.023\times {{10}^{23}}}\]
C.\[1.1\times {{10}^{-16}}\times 55.4\]
D.\[\dfrac{1.1\times {{10}^{-16}}}{{{10}^{-14}}}\]

Answer 1

Hint: We know that the ionic product of water is the product of concentration of the ions of water at a given temperature. The water molecule itself is not included while writing the expression for ionic products.

Complete answer: As we know that water is the very essential molecule for normal functioning of the body in all living organisms. Water in a pure form is made up of two molecules of hydrogen and one molecule of oxygen, which in the molecular formula is denoted as \[{{H}_{2}}O\] Pure water possesses a very weak electrolyte property which can easily undergo to the Self ionization process and spit into two molecular ions parts.
The ionization constant is the ratio of the concentration of the products to the concentration of the reactants. But in the case of ionic products of water, it is the product of the concentration of the products. Water is self-ionized but it occurs to a limited extent. When the two molecules of water collide there is a transfer of Hydrogen from one molecule to another and the product formed is hydronium ion with a positive charge and a hydroxide ion with a negative charge.
Thus \[K=\dfrac{\left[ {{H}^{+}} \right]\left[ O{{H}^{-}} \right]}{\left[ {{H}_{2}}O \right]}\]
Here we know that \[Kw=\left[ {{H}^{+}} \right]\left[ O{{H}^{-}} \right]\] also Ionic Product \[=Kw\times \left[ {{H}_{2}}O \right]\]
Also, \[{{H}_{2}}O={{H}^{+}}+O{{H}^{-}}=\dfrac{1000}{18}=55.4mole/L.\]
We have ionization constant is \[Kw=1.1\times {{10}^{-16}}\times 55.4\]
Therefore, the correct answer is option C.

Note:
Remember that due to the self-ionization of water it can act as both acid and base. When an acid or base is added to the water the ionic product of the water remains constant, but the concentration of ions changes for different types of solution.