Water Equilibrium and Acid-Base Concepts

The video explains the dissociation of water molecules into H+ and OH- ions, establishing an equilibrium system. It highlights that water is neutral due to equal concentrations of these ions. Water is compared to a weak acid, and its acid dissociation constant (Ka) is derived. The concept of the ionic product of water (KW) is introduced, showing that the concentration of water remains constant, leading to KW being a constant value.

What happens to water molecules in a sample of pure water?

• They remain completely intact.

• They evaporate immediately.

• They dissociate into H+ and OH- ions.

• They form a solid structure.

What does the equilibrium system in water involve?

• Only H2O molecules

• Only OH- ions

• H2O, H+ ions, and OH- ions

• Only H+ ions

Where does the equilibrium position lie in the dissociation of water?

• Far to the left

• In the middle

• It constantly shifts

• Far to the right

Why is pure water considered neutral?

• It has no ions at all.

• It has more OH- ions than H+ ions.

• It has more H+ ions than OH- ions.

• It has equal concentrations of H+ and OH- ions.

How can water be considered a weak acid?

• It dissociates partially, similar to weak acids.

• It forms a strong base.

• It has no dissociation.

• It dissociates completely.

What is the expression for the acid dissociation constant (Ka) of water?

• Ka = [H2O] / [H+] * [OH-]

• Ka = [OH-] / [H+]

• Ka = [H+] * [OH-] / [H2O]

• Ka = [H+] / [OH-]

What does the constant Kw represent?

• The concentration of water

• The equilibrium constant of bases

• The ionic product of water

• The dissociation constant of acids

How is Kw derived?

• By subtracting Ka from the concentration of water

• By adding Ka to the concentration of water

• By dividing Ka by the concentration of water

• By multiplying Ka with the concentration of water

What are the units of Kw?

• Moles per liter

• Moles squared per liter squared

• Moles to the power of 2 per decimeter to the power of -6

• Moles to the power of -2 per decimeter to the power of 6

Why is the concentration of water considered constant in the expression for Kw?

• Because it changes frequently

• Because it is always very high

• Because it is always zero

• Because it is negligible compared to H+ and OH- ions