Question

Ionic product of water is equal to_______.

• A. Product of $\left[{\mathrm{H}}^{+}\right]$ and $\left[{\mathrm{OH}}^{-}\right]$.
• B. Product of $\left[{\mathrm{H}}_2\mathrm{O}\right]$ and $\left[{\mathrm{H}}^{+}\right]$.
• C. Dissociation constant of water $\mathrm{x}\left[6\right]$.
• D. Dissociation constant of water $\mathrm{x}[41,012]$.

Answer 1

The correct option is A

Product of $\left[{\mathrm{H}}^{+}\right]$ and $\left[{\mathrm{OH}}^{-}\right]$.

Explanation for Correct Option:

Option (A): Product of $\left[{\mathrm{H}}^{+}\right]$ and $\left[{\mathrm{OH}}^{-}\right]$.

Ionic Product:

• The product of the concentration of ionic species in either an unsaturated or a saturated solution is known as the ionic product.
• Ionic product is also known as the solubility product when only the saturated solutions are considered.
• Therefore, the ionic products can be applied to all types of solutions.

Ionic Product of Water:

The ionic product of water is the product of the molar concentration of $\left[{\mathrm{H}}^{+}\right]$ ions and $\left[{\mathrm{OH}}^{-}\right]$ ions.

Dissociation of water can be expressed as

$\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\rightleftharpoons \underset{\mathrm{Hydrogen}\mathrm{ion}}{{\mathrm{H}}^{+}\left(\mathrm{aq}\right)}+\underset{\mathrm{Hydroxide}\mathrm{ion}}{{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$

The equilibrium constant for this reaction is,

${\mathrm{K}}_{\mathrm{C}}=\frac{\left[{\mathrm{H}}^{+}\right]\left[{\mathrm{OH}}^{-}\right]}{\left[{\mathrm{H}}_2\mathrm{O}\right]}$

We know that, ionic products,

${\mathrm{K}}_{\mathrm{W}}={\mathrm{K}}_{\mathrm{C}}\times \left[{\mathrm{H}}_2\mathrm{O}\right]$

$\therefore {\mathrm{K}}_{\mathrm{W}}=\left[{\mathrm{H}}^{+}\right]\left[{\mathrm{OH}}^{-}\right]$

Therefore, the ionic product of water is equal to product of $\left[{\mathrm{H}}^{+}\right]$ and $\left[{\mathrm{OH}}^{-}\right]$.