Lab act 9 Flashcards
If the silver nitrate has produced a precipitate insoluble in nitric acid, and the BaCl2 has
produced no precipitate.
group 1 is present
If the precipitates is orange,
FERRICYANIDE is indicated.
by adding 2 drops of ferrous sulfate Blue precipitate confirms
FERRICYANIDE.
If the precipitate is yellow,
BOMIDE and IODIDE are indicated.
add 1 ml of chloroform, 10 drops 6N HNO3 and potassium permanganate until solution turns pink then shake the mixture
An orange to brownish-red color in chloroform layer proves BROMIDE. A violet
color in chloroform layer confirms IODIDE.
If the precipitate is white:
CHLORIDE, CYANIDE, FERROCYANIDE, THOICYANATE, and
HYPOCHLORITE is indicated
.conformation of anions is done by
elimination
name of activity 9
ANALYSIS OF AN ANION OF A SOLUTION CONTAINING ONLY ONE ORGANIC COMPOUND
To 1 mL of the original sample, add 1-2 drops of ferric chloride.
a blue coloration
confirms FERROCYANIDE. A blue-red coloration proves THIOCYANATE.
To 1ml of the original sample, add 6N acetic acid, a drop at a time until the solution is acidic. Then add
1ml of lead acetate, heat the mixture and let it stand for 5 minutes.
Brown precipitate show HYPOCHLORITE.
To 1ml of original sample, add 6N NaOH until alkaline, then add a few drops of ferrous sulfate, 1 drop
of ferric chloride and heat the mixture to boiling. Allow to cool and acidify with HCl.
A blue precipitate
proves CYANIDE.
To 1ml of original sample, add 6N NaOH until alkaline, then add a few drops of ferrous sulfate, 1 drop
of ferric chloride and heat the mixture to boiling. Allow to cool and acidify with HCl.
A blue precipitate
proves CYANIDE.
4) If all of the above tests are negative, add mercurous nitrate solution in step (c-3). White precipitate
shows
chloride
If the silver nitrate has produced a precipitate soluble in HNO3, and BaCl2 has produced no
precipitate,
Group II is present.
if the precipitate is black,
SULFIDE is indicated.
Acidify 1ml of the original sample w HCl. Evolution of
Hydrogen sulfide gas confirms SULFIDE. Or to 1ml of the original sample, add few drops of lead acetate.
Formation of black precipitate confirms
SULFIDE.
if the precipitate is white, rapidly changing to brown or black,
HYPOPHOSPHITE is indicated.
To 1ml of
6N NaOH. Boil the mixture for 1 minute.
Yellow precipitate shows HYPOPHOSPHITE.
if the precipitate is white,
NITRITE and ACETATE are indicated.
Treat 1ml of the original sample with
dilute H2SO4, Allow the mixture to stand. Evolution of brown gases confirms
NITRITE
Treat 1ml of the original sample with 1ml of conc H2SO4, add 5 drops of ethyl alcohol and warm the
mixture. Evolution of gas with fruity odor confirms
ACETATE
if the silver nitrate has produced a white precipitate, soluble in HNO3, and the BaCl2 has produced a
white precipitate also soluble in HNO3,
Group III is present.
a. Acidify 1ml of the original sample with HCl. If SO2 gas is evolved and the solution remains clear,
SULFITE indicate.
To 1ml of the original sample , add 3-5 drops of BaCl2 and a drop of HCl to redissolve
the precipitate. Filter if the precipitate is not completely dissolve. To the filtrate, add 1ml of bromine
water and boil the mixture for 1-2 minutes. White precipitate confirms
SULFITE
if effervescence is produced in step (4-a) but the evolved is odorless, expose a drop of limewater in
the stirring rod to the issuing gas.
White precipitate shows CARBONATE.
c. To 1ml of the original sample in an evaporating dish, add 1ml of the conc H2SO4 and 3ml of methyl
alcohol. Stir the mixture and then light the alcohol.
A green flame coloration confirms BORATE.
To 1ml of the original sample, add CaCl2 until precipitation is complete. Then acidify the mixture with
acetic acid.
White precipitate insoluble in acetic acid shows OXALATE.
If the precipitate produced in step (4-d) is soluble in acetic acid,
TARTRATE is indicated.
To 1ml of the
original sample, add potassium acetate and acidify the mixture with acetic acid. White crystalline
precipitate proves
TARTRATE
If the CaCl2 in step (4-d) has produced no precipitate, without adding acetic acid, boil the mixture
gently for 1-2 minutes.
White precipitate shows CITRATE.
If the CaCl2 in step (4-d) has produced no precipitate, without adding acetic acid, boil the mixture
gently for 1-2 minutes.
White precipitate shows CITRATE.
- If the silver nitrate has produced a colored precipitate, soluble in HNO3 and the BaCl2 precipitate
(colored or white) is also soluble in HNO3,
HNO3, Group IV is present.
If the silver nitrate precipitate is reddish-brown,
ARSENATE and CHROMATE ARE INDICATED
indicated. To 1ml of
original sample, add 5 drops of conc HCl, 5 drops of KI and 2-3 drops of starch solution.
Blue coloration SHOWS ARSENATE
To 1ml of original sample, add few drops of lead acetate. Yellow precipitate proves
CHROMATE
To 1ml of original sample, add few drops of lead acetate. Yellow precipitate proves
CHROMATE
If the silver nitrate has produced a yellow precipitate,
PHOSPHATE and ARSENITE are indicated.
indicated. To 1ml
of original sample, add 10 drops of ammonium chloride, 1ml of magnesia mixture and as excess of
NH4OH. Allow the mixture to stand for 10 minutes.
White crystalline precipitate shows PHOSPHATE.
Acidify 1ml of the original sample with HCl and saturate with 10% thioacetamide solution. Formation
of yellow precipitate shows
ARSENITE.
e. If the silver nitrate has produced a white precipitate rapidly turning black,
THIOSULFATE
To 1ml of the original sample, add few drops of iodine. If the iodine solution is immediately decolorized,
THIOSULFATE is confirmed.
If the silver nitrate and BaCl2 have produced no precipitate,
Group V is indicated.
To 1ml of the original sample, add 1ml of conc H2SO4 and copper wire, then warm the mixture gently.
Evolution of brown gas confirms
NITRATE
To 1ml of the original sample, add 1ml of conc H2SO4 and copper wire, then warm the mixture gently.
Evolution of brown gas confirms
NITRATE
b. To 1ml of the original sample, add 2-3 drops of KNO2 and AgNO3. Acidify the mixture with HNO3.
White precipitate shows
CHLORATE
If the silver nitrate has produced no precipitate and the BaCl2 a white precipitate, insoluble in HNO3,
Group VI is present.
a. To 1ml of the original sample add a few drops of lead acetate and 1-2 mL of ammonium acetate
solution, then warm the mixture. A white precipitate soluble in the ammonium acetate solution confirm
SULFATE.
b. To 1mL of the original sample, add several drops of CaCl2. White slimy precipitate difficult to dissolve
in HCl and HNO3 but soluble in acetic acid shows
FLUORIDE.
