Question

Sodium hydroxide is classified as a strong base $(NaOH)$ . For every mole of sodium hydroxide added to a large volume of water. One mole of what ion enters in solution?

Answer 1

Hint :Sodium hydroxide is an inorganic compound, it is white solid ionic compound consisting of sodium cation $N{a}^{+}$ and hydroxide anion $O{H}^{-}$ . Sodium hydroxide is a strong base because it dissociates completely in aqueous solution to form sodium cation and hydroxide anion.

Complete Step By Step Answer:
Sodium hydroxide dissociates completely in aqueous solution forming sodium cations $N{a}^{+}$ and hydroxide anion $O{H}^{-}$ . The dissociation can be written in the form as:
 $NaOH(aq)\to N{a}^{+}(aq)+O{H}^{-}(aq)$
One formula unit of sodium hydroxide contains one sodium cation and one hydroxide anion, it follows that one mole will contain one mole of sodium cation and one mole of hydroxide anion. Every mole of sodium hydroxide dissolved in solution will produce one mole of hydroxide anions, which will affect the pH of the solution.
From the perspective of acid-base reactions, the sodium cations are of no importance in the solution. In fact, sodium hydroxide is used as a way to deliver hydroxide anions to the solution. You can thus say that every mole of sodium hydroxide dissolved in solution will produce one mole of hydroxide anions that will directly affect the pH of the solution.
The pH serves as an indicator that compares some of the most water-soluble ions. The outcome of a pH measurement is determined by a consideration between the number of $H^{+}$ ions and the number of $O{H}^{-}$ ions. When the number of hydrogen ions are equal to hydroxide ions the water is neutral.

Note :
The pH of water can vary from $0$ and $14$ , when the pH of a substance is above $7$ , it is a basic substance. When the pH is below $7$ , it is an acidic substance. The pH is a logarithmic factor, when a solution becomes ten times more acidic, the pH will fall by one unit. When a solution becomes a hundred times more acidic the pH will fall by two units.