Question

1.)When OH- and H+ ions are brought together, they quickly combine to form _____.

water molecules
hydroxide
hydronium
hydrates

2.)The number of moles of H+ ions in a liter of distilled (pure) water is:

1 x 10-7
1 x 10-14
0.5 x 10-7
2 x 10-14
none of these

3.)The ion product of water:

varies with pH
is only applicable to neutral water
remains constant regardless of the pH
ranges between 1.0 and 10-14

Answer 1

1. A
2. A (Since pH=7)
3. B

Answer 2

1) Answer is: water molecules.

Balanced chemical reaction: H⁺ + OH⁻ → H₂O.

Neutralization is is reaction in which an acid (for example hydrochloric acid HCl) and a base (for example sodium hydroxide) react quantitatively with each other. In this reaction water and salt are products of reaction.

2) Answer is: 1 x 10⁻⁷.

Water dissociates (autoionization) to form hydrogen ions (H⁺) and hydroxide (OH⁻) ions. The protons (H⁺) hydrate as hydroxonium ions (H₃O⁺).

The Kw (the ionic product for water) at 25°C is 1·10⁻¹⁴ mol²/dm⁶ or 1·10⁻¹⁴ M². Concentration of hydrogen ions and hydroxide ions in pure water are the same.

Kw = [H⁺] · [OH⁻].

[H⁺] = [OH⁻] = 1·10⁻¹⁴ mol²/dm⁶.

3) Answer is: remains constant regardless of the pH.

For example, the Kw (the ionic product for water) at 0°C is 0,12·10⁻¹⁴ mol²/dm⁶ and the Kw (the ionic product for water) at 25°C is 1·10⁻¹⁴ mol²/dm⁶.

The ion product of water only varies with different temperature.