Qualitative Analysis Flashcards
(121 cards)
1
Q
What does the qualitative scheme presented here analyze?
A
A simple mixture of two cations and two anions
For more complicated mixtures, consult textbooks on qualitative analysis.
2
Q
Why should all equipment for use in analysis be very clean?
A
To avoid wrong results due to impurities on spatulas and other equipment.
3
Q
What is recommended regarding the timing of work on a given sample?
A
Finish the work during the given period.
4
Q
When should practical report books be written up?
A
At the time experiments are performed.
5
Q
What is the first step in the qualitative report for identifying non-metallic radicals (anions)?
A
Action of dil. HCl.
6
Q
What is the second step in the qualitative report for identifying non-metallic radicals (anions)?
A
Action of conc. H2SO4.
7
Q
What is the third step in the qualitative report for identifying non-metallic radicals (anions)?
A
Preparation of Na2CO3 extract.
8
Q
What follows the preparation of Na2CO3 extract in the qualitative report?
A
Tests for acid radicals in solution.
9
Q
What is included in the qualitative report related to flame tests?
A
Flame test (where necessary).
10
Q
What is the test for ammonium radical?
A
Tests for ammonium radical (NH4+).
11
Q
What is the step after preparing the solution of sample for group separation?
A
Group separation of metal ions.
12
Q
What should be analyzed after group separation of metal ions?
A
Analysis of group precipitates for the metal ions present.
13
Q
What is the purpose of the qualitative scheme presented?
A
To analyze a simple mixture of two cations and two anions
14
Q
What should be ensured about all equipment used in analysis?
A
All equipment should be very clean
15
Q
What can lead to wrong results in qualitative analysis?
A
Presence of impurities on spatulas and equipment
16
Q
What is recommended regarding the timing of work on a sample?
A
Try to finish the work during the given period
17
Q
When should practical report books be written up?
A
At the time the experiments are performed
18
Q
What is the first step in the qualitative report for identifying metallic radicals?
A
Action of dil. HCl
19
Q
What is the second step in the qualitative report for identifying metallic radicals?
A
Action of conc. H2SO4
20
Q
What is the third step in the qualitative report?
A
Preparation of Na2CO3 extract
21
Q
What tests should be performed for acid radicals in solution?
A
Tests for acid radicals in solution
22
Q
What test is conducted where necessary?
A
Flame test
23
Q
What is tested for ammonium radical?
A
Tests for ammonium radical (NH4+)
24
Q
What is the purpose of the preparation of solution of sample for group separation?
A
To separate metal ions
25
What is the final step in the qualitative analysis procedure?
Analysis of group precipitates for the metal ions present
26
Fill in the blank: The qualitative analysis procedure should show the following test/procedure in the order given: Action of dil. HCl, Action of conc. H2SO4, Preparation of _______.
Na2CO3 extract
27
What is the third step in the qualitative report?
Preparation of Na2CO3 extract
28
What tests should be performed for acid radicals in solution?
Tests for acid radicals in solution
29
What test is conducted where necessary?
Flame test
30
What are the two main categories of radicals mentioned?
Acid Radicals and Metallic Radicals
## Footnote
This categorization is important for qualitative analysis in chemistry.
31
What is the first test performed on sample S2?
Sample S2 + Dil. HCl, heated
## Footnote
This step is part of the qualitative analysis procedure to identify acid radicals.
32
What happens when MnO4 is added to sample S2?
No gas evolved
## Footnote
This observation is significant in determining the presence of certain radicals.
33
What is the observation when AgNO3 solution is added to the Na2CO3 extract after boiling?
White ppt soluble in dilute ammonia
## Footnote
This indicates the presence of chloride ions in the sample.
34
What does the action of dilute hydrochloric acid indicate in acid radicals testing?
Carbonate, sulphate, sulphide probably absent
## Footnote
This inference helps narrow down the possible radicals in the sample.
35
What gas is evolved when testing for metallic radicals with hydrochloric acid?
Colourless gas with pungent smell
## Footnote
This observation may indicate the presence of certain metallic radicals.
36
What color is the gas evolved during the identification of chloride?
Greenish gas (Cl2) evolved
## Footnote
Chlorine is identified as a significant indicator of the presence of chloride ions.
37
Fill in the blank: The test gives indication of the presence of nearly all the common _______.
weak acids
## Footnote
This is done by adding 2M hydrochloric acid to the original sample.
38
What is the procedure for dry tests for acid radicals?
Add about 0.5 cm³ of 2M hydrochloric acid to the original sample in a test tube
## Footnote
Observations of changes and evolved gases help identify the acid radicals.
39
True or False: The identification of acid radicals requires only wet tests.
False
## Footnote
Both dry and wet tests are used for comprehensive analysis.
40
What is the purpose of boiling Na2CO3 extract with dilute HNO3?
To expel CO2
## Footnote
This step is necessary before adding AgNO3 for further analysis.
41
What are the two main categories of radicals mentioned?
Acid Radicals and Metallic Radicals
## Footnote
This categorization is important for qualitative analysis in chemistry.
42
In addition of 0.5cm3 of 2M hydrochloric acid to a sample, Effervescence of a colourless gas that turns lime water milky indicates the presence of?
CO2 from a carbonate
43
What happens to wet blue litmus paper when exposed to SO2?
Turns red
44
In addition of 0.5cm3 of 2M hydrochloric acid to a sample, what gas is produced from a sulphite that has a suffocating smell?
Colourless gas, SO2
45
What happens to lead acetate when exposed to H2S?
Blackens
46
What is produced when MnO2 is added to a chloride upon addition of 0.5cm3 of H2SO4?
Greenish gas evolved
47
What type of gas is identified with a pungent smell and white fumes with NH4OH?
HCl
48
What is produced when MnO2 is added to a bromide upon addition of 0.5cm3 of conc. H2SO4?
More red fumes are produced
49
Fill in the blank: The reddish coloured acid vapour with a pungent smell comes from a _______.
Bromide
50
What gas is produced from a bromide that results in reddish acid vapour?
HBr
51
What is the inference upon addition of 0.5cm3 of H2SO4 to a sample for the observation below
"Oil drops on the wall of the test tube, pungent acid fumes often coloured brown"
HNO3 and NO2 from a nitrate
52
What happens when copper turnings are added to a nitrate upon addition of.5cm3 of H2SO4?
Deepens the brown colour of the pungent acid fume
53
True or False: Iodides produce a violet acid vapour accompanied by HI.
True
54
What is the confirmatory test for carbonate?
Add potassium dichromate and 2M hydrochloric acid, warm if necessary. Evolution of carbon dioxide confirms carbonate presence.
## Footnote
The carbon dioxide turns lime water milky.
55
What is the principle behind tests for acid radicals in solution?
Precipitation tests where heavy metals may interfere, requiring their removal by treatment with excess sodium carbonate.
## Footnote
Heavy metals like Pb, Ca, Ag can affect analysis.
56
What happens when PbSO₄ reacts with excess Na₂CO₃?
Produces PbCO₃ (solid), Na₂SO₄ (in solution), and excess Na₂CO₃ .
## Footnote
The solid precipitate is removed by filtration.
57
What is the procedure for preparing a sodium carbonate extract?
Boil a sample with sodium carbonate in distilled water, then filter or centrifuge to obtain the Na₂CO₃ extract.
## Footnote
This extract is used for further tests.
58
How do you test for sulphate using Na₂CO₃ extract?
Add dilute HCl to Na₂CO₃ extract, boil, then add BaCl₂. A white precipitate insoluble in dilute HCl indicates sulphate.
## Footnote
Ba(NO₃)₂ can also be used, with a white precipitate in dilute HNO₃ indicating sulphate.
59
Fill in the blank: To test for halides, a small quantity of the sample is boiled with _______ of solid sodium carbonate.
1 gm
60
What indicates the presence of sulphate when testing with BaCl₂?
A white precipitate insoluble in dilute HCl.
## Footnote
Alternative tests can use Ba(NO₃)₂.
61
What is the role of boiling in the preparation of sodium carbonate extract?
To destroy excess Na₂CO₃ before adding further reagents.
## Footnote
This ensures accurate test results.
62
True or False: The filtrate from the reaction of PbSO₄ with Na₂CO₃ contains the acid radical to be identified.
True
63
To a small amount (0.5cm3) of Na₂CO₃ extract, add excess dilute HNO3. Boil to destroy excess Na₂CO₃; add few drops of AgNO3 solution then add dilute ammonia solution.
White ppt soluble in dilute ammonia indicates the presence of?
A chloride
64
To a small amount (0.5cm3) of Na₂CO₃ extract, add excess dilute HNO3. Boil to destroy excess Na₂CO₃; add few drops of AgNO3 solution then add dilute ammonia solution.
Cream ppt. sparingly soluble in dilute ammonia indicates the presence of?
Bromide
65
To a small amount (0.5cm3) of Na₂CO₃ extract, add excess dilute HNO3. Boil to destroy excess Na₂CO₃; add few drops of AgNO3 solution then add dilute ammonia solution. Yellow ppt. insoluble in dilute ammonia indicates the presence of?
Iodine
66
In confirmation of bromide
Acidify a small amount (~0.5cm3) of the Na2CO3 extract with ________. Add ______ till brown colour appears, then add two drops of _____________. A/An ____________________ shows the presence of a bromide
2M HCl acid
Chlorine water
Carbon tetrachloride, CCl4 and shake
An orange or red colour in the CCl4 layer
67
Hydrated Mn and Co salts are ________coloured compound
Pink
68
Dissolve a tiny crystal of sodium nitroprusside in 1-2cm³ of water. To a small amount of this solution, add a few drops of the Na2CO3 extract. A purple colouration shows the presence of a ___________
Sulphide
69
CdS, AsS, SnS, PbI2, ferric chloride and nitrate are ________coloured compounds
Yellow
70
Anhydrous cobalt salts, hydrated cupric salts are ________coloured compounds
Blue
71
To a small amount (0.5cm3) of Na₂CO₃ extract, add excess dilute HNO3. Boil to destroy excess Na₂CO₃; add few drops of AgNO3 solution then add dilute ammonia solution.
White ppt soluble in dilute ammonia indicates the presence of?
A chloride
72
In the test for Nitrate using Na2CO3 extract
Acidify a small amount (0.5cm3) of the Na2CO3 extract with _________________ and boil to destroy excess Na2CO3. Cool and add equal volume of _________________________. Holding the tube in a ______________position carefully add _________________down the side of the tube. A ____________ ring indicates the presence of a nitrate.
2M sulphuric acid
Fresh saturated ammonium sulphate solution
Slanting
Concentrated sulphuric acid
Dark brown
73
Dissolve a tiny crystal of sodium nitroprusside in 1-2cm³ of water. To a small amount of this solution, add a few drops of the Na2CO3 extract. A purple colouration shows the presence of a ___________
Sulphide
74
CdS, AsS, SnS, PbI2, ferric chloride and nitrate are ________coloured compounds
Yellow
74
HgCl2, HgS and Sb2S3 are ____ coloured compound
Red
75
Hg2I2, CrCl3, ferrous salts, nickel salts, CaCl2, CuCO3 are _________ coloured salts
Green
76
PbS, CuS, HgS, FeS, NiS, Ag2S, MnO2, CoS are ________coloured compound
Black
77
________gives blue colour when dissolved in dilute acids
Cupric Copper salts samples
78
____________gives green colour when dissolved in dilute acids
Nickel, Ferrous Iron , Chromic (chromium)
79
_________gives yellow colour when dissolved in dilute acids
Chromates, ferric iron
80
_________gives pink colour when dissolved in dilute acids
Cobalt or Manganese salts
81
In flame test
Moisten small of the sample with a drop of ________
conc. HCl
82
In flame test
Hold the bottom end of the test tube that has been dipped in the moistened sample at the outside edge of a _______________ bunsen flame
Non-luminous
83
What colour does sodium give in flame test
Persistent Golden yellow
84
Which metal gives Blood red (scarlet red) in flame test
Strontium
85
What colour is observed when colour imparted by flame test of Strontium metal is viewed through a cobalt glass
Purple
86
Potassium gives what colour in flame test
Violet (lilac)
87
What colour is observed when colour imparted by flame test of potassium metal is viewed through a cobalt glass
Lilac(light purple)
88
Which metal gives brick red colour in flame test
Calcium
89
What colour is observed when colour imparted by flame test of Calcium metal is viewed through a cobalt glass
Light green
90
Barium gives what colour in flame test
Pale Green 🍏 apple colour
91
What colour is observed when colour imparted by flame test of Barium metal is viewed through a cobalt glass
Blue green
92
_______metal gives Bluish green colour in flame test
Copper
93
What colour is observed when colour imparted by flame test of copper metal is viewed through a cobalt glass
Green
94
Arsenic gives ______colour in flame test
Pale blue
95
Bismuth gives ________ colour in flame test
Pale blue
96
Lead gives ________colour in flame test
Pale blue
97
Antimony gives ________ colour in flame test
Pale blue
98
A certain metal gives pale blue flame in flame test when that flame is viewed through cobalt glass what colour is seen
Pale blue
99
In test for Ammonium radical
Warm a bit of the original sample with ________
2M NaOH
100
Ammonia when passed through Nessler's reagent yields?
Orange brown precipitate or colouration
101
Ammonia blackens ______________paper
Mercurous nitrate
102
In preparation of solution of the sample for identification of Metallic ions in solution, a solution on the sample for analysis is first made. Solvent are tried in which order
I) Water
II) Dilute hydrochloric acid
III) Conc. Hydrochloric acid
IV) Dilute Nitric acid
V) Conc. Nitric acid
VI) Aqua regia
103
What are the components of Aqua regia
1vol. conc. HNO3 + 3 vols. Conc. HCl
104
In preparation of solution of the sample for identification of metallic ion in solution
In testing for solubility in a solvent,use only very small quantity of the sample.True or False
True
105
In preparation of solution of the sample for identification of metallic ion in solution.
In all cases of solution making, there must no be residual solid or particle. True or False
True
106
What colour is observed when colour imparted by flame test of Barium metal is viewed through a cobalt glass
Blue green
107
Separation of metallic ion into groups is based on the fact that the solubility of many metallic chloride, hydroxide, sulphide, and carbonates are _______
Very small
108
The precipitation agent for chlorides in Metallic ions identification is_______
Dil HCl
109
Which metallic ions are precipitated using Dil HCl
Ag+, Hg+ and Pb²+
110
In metallic ion identification H2S(acidic) is the precipitation agent for
Sulphide
111
112
113
Which metallic ions are precipitated using H2S
Cu²+, Hg²+, Pb²+, Bi²+
114
NH4OH is the precipitation for
Hydroxide
115
Al³+ is precipitated using
NH4OH
116
H2S(alkaline) is the precipitation agent for the sulphide of which metallic ions
Zn²+, Ni²+, Co²+ and Mn²+
116
(NH4)CO3 is the precipitation agent for _______form of ppt
Carbonate
117
(NH4)2CO3 is the precipitation agent for which metallic ions
Ca²+, Ba²+ and Sr²+
118
In group separation which metallic ions remain in solution after all the other metals have been precipitated
Mg²+, Na+ and K+
119
NH4OH is the precipitation agent for which metallic ions
Al³+, Cr³+ and Fe³+
