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Updating a Water Model After Proton Transfer 4 questions
Updating a Water Model After Proton Transfer
Base your answers on the information provided and your knowledge of chemistry. Use the 2025 Chemistry Reference Tables as needed.
A class updates a display about hydrogen chloride entering water. In its model, an HCl molecule transfers a hydrogen ion to a water molecule. The two electrons in the original H–Cl bond stay with chlorine. The water molecule uses one of its oxygen lone pairs to form a bond to the added hydrogen.
HCl(g) + H2O(l) → H3O+(aq) + Cl-(aq)
Question 1
Before the transfer, water has two O–H bonds and two lone pairs on oxygen. Describe how both counts change when it becomes H₃O⁺.
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Question 2
Which statement fits the chlorine model after transfer?
- Chlorine keeps the original H–Cl bond pair and becomes Cl⁻.
- Chlorine loses the original H–Cl bond pair and becomes Cl⁺.
- Chlorine keeps the hydrogen nucleus and stays as HCl.
- Chlorine gains one proton and changes element.
In the display, an oxygen center with three bonded hydrogen atoms and one lone pair gives a trigonal pyramidal model. A center with two bonded hydrogen atoms and two lone pairs gives a bent model.
Question 3
How should the student revise a bent water drawing to represent the oxygen center in the product? Name the new shape and identify what changed.
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Question 4
The student draws H₃O⁺ but leaves the separate chlorine atom neutral. Use charge balance to explain why that drawing is inconsistent with the equation.
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