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What is the net ionic equation for the following molecular equation? $$ \mathrm{HF}(a q)+\mathrm{KOH}(a q) \longrightarrow \mathrm{KF}(a q)+\mathrm{H}_{2} \mathrm{O}(I) $$ Hydrofluoric acid, HF, is a molecular substance and a weak electrolyte. a. \(\mathrm{H}^{+}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}(l)\) b. \(\mathrm{H}^{+}(a q)+\mathrm{KOH}(a q) \longrightarrow \mathrm{K}^{+}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\) c. \(\mathrm{HF}(a q)+\mathrm{KOH}(a q) \longrightarrow \mathrm{K}^{+}(a q)+\mathrm{F}^{2}(a q)\) d. \(\mathrm{HF}(a q)+\mathrm{K}^{+}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow \mathrm{KF}(a q)+\mathrm{H}_{2} \mathrm{O}(I)\) e. \(\mathrm{HF}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow \mathrm{F}^{-}(a q)+\mathrm{H}_{2} \mathrm{O}(l)\)

Step by step solution

01

Write the balanced molecular equation

The given molecular equation is \( \text{HF}(aq) + \text{KOH}(aq) \rightarrow \text{KF}(aq) + \text{H}_2\text{O}(l) \). This equation is already balanced with all the coefficients equal to one.

02

Identify the nature of each substance

In this reaction, HF is a weak acid (weak electrolyte), KOH is a strong base (strong electrolyte), and KF is a soluble salt (strong electrolyte). Water is a stable molecule and doesn't ionize in this reaction.

03

Write the complete ionic equation

Since HF is a weak acid, it remains mostly in molecular form: \( \text{HF}(aq) + \text{K}^+(aq) + \text{OH}^-(aq) \rightarrow \text{K}^+(aq) + \text{F}^-(aq) + \text{H}_2\text{O}(l) \)

04

Remove spectator ions to find the net ionic equation

The spectator ion in this reaction is \( \text{K}^+ \) since it appears on both sides of the equation without changing. Removing \( \text{K}^+ \) from the complete ionic equation, we have: \( \text{HF}(aq) + \text{OH}^-(aq) \rightarrow \text{F}^-(aq) + \text{H}_2\text{O}(l) \)

05

Write the net ionic equation

The net ionic equation, showing only the species that undergo a chemical change, is: \( \text{HF}(aq) + \text{OH}^-(aq) \rightarrow \text{F}^-(aq) + \text{H}_2\text{O}(l) \)

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Weak Electrolyte

A weak electrolyte is a substance that partially dissociates into ions when dissolved in water. This incomplete dissociation is what defines weak electrolytes. In the provided reaction, hydrofluoric acid (HF) is a classic example of a weak electrolyte.
HF, when dissolved in water, only dissociates slightly into hydrogen ions and fluoride ions:

• Only a small fraction of HF molecules break apart into \( \text{H}^+ \) and \( \text{F}^- \) ions.
• Most of the HF remains in molecular form, which is why it is considered weak.

This limited ionization is what makes HF an interesting component in chemical reactions, as it often leads to net ionic equations that don't immediately showcase its ionic nature.

Strong Base

Strong bases are substances that completely dissociate into ions in aqueous solutions. Potassium hydroxide (KOH) is a strong base. Let's see why.
When KOH is dissolved in water, it separates entirely into potassium ions and hydroxide ions:

• Every unit of KOH splits into \( \text{K}^+ \) and \( \text{OH}^- \) ions.
• This complete dissociation allows strong bases to neutralize acids very effectively by providing hydroxide ions.

In the given reaction, the strong base KOH plays a crucial role, as it reacts with HF, the weak electrolyte, and produces water and fluoride ions, demonstrating complete ionization.

Spectator Ion

Spectator ions are ions that exist in the same form on both the reactant and the product side of a chemical equation. They do not participate in the actual chemical change and are thus considered inactive in the context of the reaction.
In the provided ionic equation of the reaction between HF and KOH, the potassium ion \( \text{K}^+ \) is a spectator ion:

• It appears unchanged on both sides of the complete ionic equation.
• Removing spectator ions helps us in identifying the net ionic equation by showing only the substances that undergo a chemical transformation.

Understanding which ions are spectators helps to simplify reactions and focus on the actual chemical change happening, like the interaction between HF and \( \text{OH}^- \).

Chemical Reaction

A chemical reaction involves the transformation of reactants into products, usually showcasing changes primarily at the molecular level. In this exercise, the reaction between hydrofluoric acid (HF) and potassium hydroxide (KOH) is a classic acid-base reaction.
Key points to consider in this reaction include:

• HF as the acidic component, reacting with \( \text{OH}^- \) from KOH.
• Formation of water \( \text{H}_2\text{O} \) as a product, a common result in acid-base reactions.
• The net ionic equation highlighting the essential chemistry without extraneous details (such as spectator ions): \( \text{HF}(aq) + \text{OH}^-(aq) \rightarrow \text{F}^-(aq) + \text{H}_2\text{O}(l) \).
• The reaction showcases an exchange of ions, resulting in the formation of new substances (like water and fluoride ions) as opposed to the simple presence of the original reactants.

Understanding the details of chemical reactions helps in predicting products, balancing equations, and gaining insights into reaction conditions.