silver - 2025 ACF Regionals

Question

Some zinc-containing batteries use an unusual tetroxide of this element containing cations in the plus-one and plus-three oxidation states. For 10 points each:

[10m] Name this element whose plus-one cation is central in a diamine complex that precipitates out upon acting as an oxidizing agent. This element’s nitrate is used as a test for chloride ions.

ANSWER: silver [or Ag]

[10e] The formation of a “silver mirror” is a positive result in Tollens’ test, which distinguishes types of this functional group defined by a C–O double bond.

ANSWER: carbonyl [accept aldehyde or ketone]

[10h] Silver(I) (“silver one”) catalysts are a common choice for this reaction that starts with a diazoketone. This reaction’s ketene intermediate can undergo a two-plus-two cycloaddition to form a four-membered ring.

ANSWER: Wolff rearrangement [prompt on rearrangement]

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Summary


California	2025-02-01	Y	3	10.00	67%	33%	0%
Great Lakes	2025-02-01	Y	5	8.00	60%	20%	0%
Lower Mid-Atlantic	2025-02-01	Y	6	6.67	50%	17%	0%
Midwest	2025-02-01	Y	6	15.00	100%	50%	0%
North	2025-02-01	Y	3	10.00	67%	33%	0%
Overflow	2025-02-01	Y	5	10.00	60%	40%	0%
Pacific Northwest	2025-02-01	Y	2	20.00	100%	100%	0%
South Central	2025-02-01	Y	2	15.00	50%	100%	0%
Southeast	2025-02-01	Y	4	10.00	75%	25%	0%
UK	2025-02-01	Y	10	13.00	40%	70%	20%
Upper Mid-Atlantic	2025-02-01	Y	8	13.75	88%	50%	0%
Upstate NY	2025-02-01	Y	3	6.67	67%	0%	0%

Data


Claremont A	UCLA	0	10	0	10
Claremont B	UC Berkeley A	0	0	0	0
UC Berkeley B	UCSD	10	10	0	20
Carnegie Mellon A	Ohio State A	0	10	0	10
Michigan D	Carnegie Mellon B	0	0	0	0
Case Western B	Case Western A	10	10	0	20
Michigan A	Michigan State	0	10	0	10
Ohio State B	Kenyon	0	0	0	0
William & Mary	Duke	0	10	0	10
UNC B	Liberty A	0	10	0	10
Liberty C	UNC D	10	0	0	10
South Carolina	Virginia Tech A	0	10	0	10
Liberty B	UNC C	0	0	0	0
Virginia A	Wake Forest	0	0	0	0
Chicago B	Chicago A	10	10	0	20
Chicago D	Missouri S&T	10	10	0	20
Illinois B	Indiana B	0	10	0	10
WashU A	Illinois C	10	10	0	20
Illinois A	Indiana A	0	10	0	10
Chicago C	Missouri	0	10	0	10
Carleton	Wisconsin A	0	0	0	0
Iowa State	Winona State	10	10	0	20
Minnesota B	Wisconsin B	0	10	0	10
Georgetown A	Stanford B	0	0	0	0
Georgetown B	Northwestern A	0	0	0	0
Iowa	Notre Dame B	0	10	0	10
Purdue	Northwestern B	10	10	0	20
Notre Dame A	Notre Dame C	10	10	0	20
Alberta	UW A	10	10	0	20
UBC	UW B	10	10	0	20
TAMU	Texas A	10	0	0	10
ASU	Texas B	10	10	0	20
Georgia Tech C	Alabama A	10	10	0	20
Louisville A	Vanderbilt A	0	0	0	0
Georgia Tech D	Tennessee A	0	10	0	10
Bruin A	Georgia Tech B	0	10	0	10
Oxford B	Cambridge A	0	0	0	0
Cambridge E	Cambridge C	10	10	0	20
Cambridge B	Cambridge D	10	0	0	10
Imperial A	Durham	10	10	0	20
LSE	Imperial B	10	0	10	20
Manchester	Warwick A	10	10	0	20
Oxford A	Warwick B	10	0	10	20
Southampton A	Oxford C	0	0	0	0
Bristol	Sheffield	0	0	0	0
Southampton B	NYU C	10	10	0	20
Columbia B	Haverford B	10	10	0	20
Cornell B	Columbia C	10	10	0	20
Maryland B	Penn B	0	0	0	0
NYU B	George Washington A	0	10	0	10
Penn A	George Washington B	10	10	0	20
Yale A	Vassar A	0	10	0	10
ESF A	Cornell D	0	0	0	0
RIT A	Cornell C	0	10	0	10
Binghamton A	RIT B	0	10	0	10
NYU A	John Jay College	10	10	0	20
Johns Hopkins A	Rutgers A	0	10	0	10