This Is a True Story; Can You Explain What Happened $$E _ { \text {red } } ^ { \circ }$$

question 124

Multiple Choice

This is a true story; can you explain what happened? Prior to a really important dinner party, the hostess discovered that her silverware was very tarnished. She needed a quick fix. She remembered reading that the tarnish (Ag₂S) would be removed if you immersed the silverware in a hot solution of baking soda (NaHCO₃) in a pan lined with aluminum foil. So she did, and so it was, but she noticed a bit of a rotten egg smell (H₂S) being produced. MetalMetal ion
$$E _ { \text {red } } ^ { \circ }$$
silver/silver(I) $\quad \quad\quad\quad\quad0.799$
aluminum/aluminum(III) $\quad- 1.677$

• A) Aluminum ions react with S^2-, form an aluminum sulfide precipitate, and gaseous carbon dioxide is released.
• B) Silver ions in the presence of the baking soda, (NaHCO₃), oxidize the sulfide to elemental sulfur that attacks the aluminum foil, which produces the smelly aluminum sulfide.
• C) The aluminum acts as a reducing agent for the silver(I) in the silver sulfide; then the bicarbonate ion protonates the sulfide ion that is released.
• D) Aluminum is plated onto the silver surface, making it shiny again, and then the reaction of the bicarbonate with the aluminum oxide releases CO₂.
• E) Silver in Ag₂S reduces the aluminum, becomes metallic silver in the process, and releases hydrogen sulfide, H₂S.

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Definitions:

Systematic Desensitization

A behavioral therapy technique used to reduce phobic responses and anxieties by gradual exposure to the feared object or situation.

Cognitive Therapy

A form of psychotherapy that emphasizes the importance of modifying dysfunctional thoughts and beliefs to improve emotional and behavioral outcomes.

Test Beliefs

Ideas or assumptions that are evaluated or verified through the process of testing or experimentation.

Assumptions

Accepted beliefs or statements taken for granted without proof.