Lab act 9

Question 1

If the silver nitrate has produced a precipitate insoluble in nitric acid, and the BaCl2 has
produced no precipitate.

Answer 1

group 1 is present

Question 2

If the precipitates is orange,

Answer 2

FERRICYANIDE is indicated.

Question 3

by adding 2 drops of ferrous sulfate Blue precipitate confirms

Answer 3

FERRICYANIDE.

Question 4

If the precipitate is yellow,

Answer 4

BOMIDE and IODIDE are indicated.

Question 5

add 1 ml of chloroform, 10 drops 6N HNO3 and potassium permanganate until solution turns pink then shake the mixture

Answer 5

An orange to brownish-red color in chloroform layer proves BROMIDE. A violet
color in chloroform layer confirms IODIDE.

Question 6

If the precipitate is white:

Answer 6

CHLORIDE, CYANIDE, FERROCYANIDE, THOICYANATE, and
HYPOCHLORITE is indicated

Question 7

.conformation of anions is done by

Answer 7

elimination

Question 8

name of activity 9

Answer 8

ANALYSIS OF AN ANION OF A SOLUTION CONTAINING ONLY ONE ORGANIC COMPOUND

Question 9

To 1 mL of the original sample, add 1-2 drops of ferric chloride.

Answer 9

a blue coloration
confirms FERROCYANIDE. A blue-red coloration proves THIOCYANATE.

Question 10

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.

Answer 10

Brown precipitate show HYPOCHLORITE.

Question 11

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.

Answer 11

A blue precipitate
proves CYANIDE.

Question 12

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.

Answer 12

A blue precipitate
proves CYANIDE.

Question 13

4) If all of the above tests are negative, add mercurous nitrate solution in step (c-3). White precipitate
shows

Answer 13

chloride

Question 14

If the silver nitrate has produced a precipitate soluble in HNO3, and BaCl2 has produced no
precipitate,

Answer 14

Group II is present.

Question 15

if the precipitate is black,

Answer 15

SULFIDE is indicated.

Question 16

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

Answer 16

SULFIDE.

Question 17

if the precipitate is white, rapidly changing to brown or black,

Answer 17

HYPOPHOSPHITE is indicated.

Question 18

To 1ml of
6N NaOH. Boil the mixture for 1 minute.

Answer 18

Yellow precipitate shows HYPOPHOSPHITE.

Question 19

if the precipitate is white,

Answer 19

NITRITE and ACETATE are indicated.

Question 20

Treat 1ml of the original sample with
dilute H2SO4, Allow the mixture to stand. Evolution of brown gases confirms

Answer 20

NITRITE

Question 21

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

Answer 21

ACETATE

Question 22

if the silver nitrate has produced a white precipitate, soluble in HNO3, and the BaCl2 has produced a
white precipitate also soluble in HNO3,

Answer 22

Group III is present.

Question 23

a. Acidify 1ml of the original sample with HCl. If SO2 gas is evolved and the solution remains clear,

Answer 23

SULFITE indicate.

Question 24

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

Answer 24

SULFITE

Question 25

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.

Answer 25

White precipitate shows CARBONATE.

Question 26

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.

Answer 26

A green flame coloration confirms BORATE.

Question 27

To 1ml of the original sample, add CaCl2 until precipitation is complete. Then acidify the mixture with
acetic acid.

Answer 27

White precipitate insoluble in acetic acid shows OXALATE.

Question 28

If the precipitate produced in step (4-d) is soluble in acetic acid,

Answer 28

TARTRATE is indicated.

Question 29

To 1ml of the
original sample, add potassium acetate and acidify the mixture with acetic acid. White crystalline
precipitate proves

Answer 29

TARTRATE

Question 30

If the CaCl2 in step (4-d) has produced no precipitate, without adding acetic acid, boil the mixture
gently for 1-2 minutes.

Answer 30

White precipitate shows CITRATE.

Question 31

If the CaCl2 in step (4-d) has produced no precipitate, without adding acetic acid, boil the mixture
gently for 1-2 minutes.

Answer 31

White precipitate shows CITRATE.

Question 32

5. If the silver nitrate has produced a colored precipitate, soluble in HNO3 and the BaCl2 precipitate
   (colored or white) is also soluble in HNO3,

Answer 32

HNO3, Group IV is present.

Question 33

If the silver nitrate precipitate is reddish-brown,

Answer 33

ARSENATE and CHROMATE ARE INDICATED

Question 34

indicated. To 1ml of
original sample, add 5 drops of conc HCl, 5 drops of KI and 2-3 drops of starch solution.

Answer 34

Blue coloration SHOWS ARSENATE

Question 35

To 1ml of original sample, add few drops of lead acetate. Yellow precipitate proves

Answer 35

CHROMATE

Question 36

To 1ml of original sample, add few drops of lead acetate. Yellow precipitate proves

Answer 36

CHROMATE

Question 37

If the silver nitrate has produced a yellow precipitate,

Answer 37

PHOSPHATE and ARSENITE are indicated.

Question 38

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.

Answer 38

White crystalline precipitate shows PHOSPHATE.

Question 39

Acidify 1ml of the original sample with HCl and saturate with 10% thioacetamide solution. Formation
of yellow precipitate shows

Answer 39

ARSENITE.

Question 40

e. If the silver nitrate has produced a white precipitate rapidly turning black,

Answer 40

THIOSULFATE

Question 41

To 1ml of the original sample, add few drops of iodine. If the iodine solution is immediately decolorized,

Answer 41

THIOSULFATE is confirmed.

Question 42

If the silver nitrate and BaCl2 have produced no precipitate,

Answer 42

Group V is indicated.

Question 43

To 1ml of the original sample, add 1ml of conc H2SO4 and copper wire, then warm the mixture gently.
Evolution of brown gas confirms

Answer 43

NITRATE

Question 44

To 1ml of the original sample, add 1ml of conc H2SO4 and copper wire, then warm the mixture gently.
Evolution of brown gas confirms

Answer 44

NITRATE

Question 45

b. To 1ml of the original sample, add 2-3 drops of KNO2 and AgNO3. Acidify the mixture with HNO3.
White precipitate shows

Answer 45

CHLORATE

Question 46

If the silver nitrate has produced no precipitate and the BaCl2 a white precipitate, insoluble in HNO3,

Answer 46

Group VI is present.

Question 47

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

Answer 47

SULFATE.

Question 48

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

Answer 48

FLUORIDE.