30 Questions
What color change is observed when BaCl2 solution is added to a solution containing Iodide Ion (I2)?
Yellow precipitate
How is Iodine vapor liberated when concentrated H2SO4 decomposes iodides?
It forms a blue/violet gas
What is the result of mixing a solution containing nitrate ions with MnCl2 and HCl?
Brown gas evolution
How can oxidizing agents be detected in the presence of Iodide ions?
By reacting with iodine to form a blue to black color with starch solution
What color does the solution containing nitrate ions turn during the Brown-Ring Test when mixed with FeSO4 solution underlaid with conc’d?
Brown
In the detection process described, what color change indicates the presence of gaseous oxidizers?
Blue to black
Which of the following reactions occurs when an acidified solution of KMnO4 is treated with sulfite ion (SO3)?
2 MnO4 + 6H + 5 SO3 → 2 Mn(II) + 5 SO4 + 3 H2O
How does the sulfite ion (SO3) reduce ferric ions (Fe3+) to ferrous ions (Fe2+)?
2 Fe(III) + SO3 + H2O → 2 Fe(II) + SO4 + 2 H+
What is the reaction that occurs when sulfur dioxide (SO2) gas from sulfites reacts with Ba(OH)2 solution?
SO2 + Ba(OH)2 → BaSO3 (white ppt)
How does the sulfite ion (SO3) decolorize a fuchsin (magenta) solution?
The sulfite ion reduces the fuchsin dye to a colorless compound.
What is the reaction that occurs when a sulfide ion (S2-) is treated with dilute hydrochloric acid (HCl)?
S2- + 2 H+ → H2S
How does the thiocyanate ion (SCN-) react with silver nitrate (AgNO3) solution?
SCN- + AgNO3 → AgSCN (white ppt)
What color does a solution containing FeSO4 in a basic medium change to upon acidification?
Red
In the presence of HCl, what gas may be produced from a reaction involving cyanide ion (CN-)?
Hydrogen cyanide (HCN)
What is the yellow precipitate formed when Arsenate Ion reacts with FeCl3 in Ammonium Acetate solution?
Ferric arsenate
Which of the following solutions does NOT result in a precipitate in a dilute solution according to the text?
BaCl2 solution
What is the color change observed when a solution containing MnCl2 and HCl changes from pink to brown?
Green to red
What color precipitate is formed when AgNO3 reacts with Arsenite Ion in a neutral solution?
Yellow
What does the reaction between 2 cyanide ions (CN-) and ammonium polysulfide form?
(NH4)6SCN
What is the product obtained when Arsenite Ion reacts with Ammonium Molybdate solution and is heated with HNO3?
Arsenate Ion
In Borate Ion reactions, what is the color change observed when Turmeric paper is dipped in HCl solution?
Yellow to Red
Which ion, when reacting with Ferric ion, produces a Red color?
[Fe(CN)6^-3]
What happens when Borate Ion reacts with AgNO3 in a slightly acidic solution?
White precipitate forms
When Arsenite Ion reacts with KI Solution and acid, what is the observed reaction product?
$I_2$
Which compound is formed when cobalt oxide reacts with borax in the borax bead test?
Co(BO2)2
Which reagent is used to oxidize bromide ions to free bromine in the bromide ion test?
Potassium permanganate (acidified)
Which reaction occurs when bromide ions are treated with concentrated sulfuric acid and heated?
2HBr + H2SO4 --→ Br2 + SO2 + 2H2O
Which ion interferes with the bromide ion test by reacting with the reducing agent?
Cyanide ion (CN-)
Which reagent is used to detect the presence of carbonate ions by forming a white precipitate that dissolves in excess carbon dioxide?
Lime water
Which statement is true about the reaction between ferric nitrate and bromide ions?
Ferric nitrate does not oxidize bromide ions but oxidizes iodide ions.
Study Notes
Cyanide Ion (CN-)
- Reacts with dilute HCl to form HCN gas, which is a deadly poison
- Forms a deep blue-green color or precipitate with FeSO4 solution in a basic medium
- Forms a red color with Ferric ion (Fe3+) and ammonium polysulfide
- Reacts with AgNO3 to form a white precipitate of AgCN, which dissolves in excess cyanide
Ferricyanide Ion [Fe(CN)6-3]
- Slowly decomposes in dilute HCl
- Reacts with BaCl2 to form no precipitate
- Reacts with AgNO3 to form a red solid precipitate of Ag3Fe(CN)6, which may be soluble in saturated NaCl solution
- Reacts with MnCl2 and HCl solution to form a pink color that changes to brown
Ferrocyanide Ion [Fe(CN)6-4]
- Does not decompose in dilute HCl
- Reacts with BaCl2 to form a white precipitate of Ba2Fe(CN)6
- Reacts with AgNO3 to form a white precipitate of Ag4Fe(CN)6
Iron Salts
- Ferrous ion (Fe2+) gives a dark-blue precipitate of Fe3[Fe(CN)6]2
- Ferric ion (Fe3+) gives a brownish to green solution, but no precipitate
Cadmium Salts
- Insoluble in acidic solution
Sulfite Ion (SO3)
- Oxidizing agents, such as acidified KMnO4 solution, decolorize the solution
- Reduces Ferric ions to Ferous ions
- Reacts with starch to liberate iodine, which is indicated by a blue color on the paper
- Reacts with Ba(OH)2 solution to form a white precipitate of BaSO3
Sulfide Ion (S2)
- Reacts with dilute HCl to form an immediate evolution of H2S
- Reacts with BaCl2 solution to form no reaction
- Reacts with AgNO3 solution to form a black precipitate of Ag2S
- Reacts with sodium nitroprusside solution to form a purple color
Thiocyanate Ion (SCN)
- Reacts with dilute HCl to form no visible effect
- Reacts with AgNO3 to form a white precipitate of AgSCN, which dissolves in excess cyanide ion
Arsenate Ion (AsO4)
- Reacts with FeCl3 in ammonium acetate solution to form a yellowish-white precipitate of Fe2(HAsO4)3 or FeAsO4
- Reacts with ammonium molybdate solution to form a yellow precipitate
Arsenite Ion (AsO3)
- Reacts with dilute HCl to form no visible effect
- Reacts with BaCl2 in NH4OH solution to form a white precipitate of Ba3(AsO3)2
- Reacts with AgNO3 to form a yellow precipitate of Ag3AsO3
- Reacts with H2S to form a yellow precipitate of As2S3
Borate Ion (BO2)
- Reacts with dilute HCl to form no visible effect
- Reacts with BaCl2 solution to form a white precipitate of Ba(BO2)2
- Reacts with AgNO3 solution to form a white precipitate of AgBO2
- Reacts with C2H5OH and con'd H2SO4 to form a green flame when ignited
Iodide Ion (I2)
- Reacts with dilute HCl to form no visible effect
- Reacts with con'd H2SO4 to form a violet color when warmed
- Reacts with BaCl2 solution to form no reaction
- Reacts with AgNO3 solution to form a yellow precipitate of AgI, which is insoluble in ammonia solution
Nitrate Ion (NO3)
- Reacts with dilute HCl to form no visible effect
- Reacts with con'd H2SO4 to form a brown gas of NO2
- Reacts with BaCl2 solution to form no reaction
- Reacts with AgNO3 solution to form no reaction
- Reacts with MnCl2 and HCl solution to form a pink color that changes to brown
Bromide Ion (Br2)
- Reacts with dilute HCl to form no visible reaction
- Reacts with con'd H2SO4 to form a reddish-brown vapor of Br2
- Reacts with BaCl2 solution to form no reaction
- Reacts with AgNO3 solution to form a pale yellow precipitate of AgBr, which is insoluble in 0.25M NH4OH and in HNO3 but soluble in con'd NH4OH
Test your knowledge on chemical reactions involving arsenate and arsenite ions. Identify the products formed in various reactions such as with ammonium, molybdate, phosphoric acid, and other reagents.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
