Qualitative Analysis

1/4/2016

Embibe

Currency Earned 235 embiums Go to Dashboard x

Congratulations! You have attempted all the questions in Qualitative Analysis !

Greater the attempts higher the scores, Take a different Practice through the Dashboard and improve your Test taking skills.

Go to Dashboard

x

Terminating Practice Test

Are you sure you want to exit practice test for Qualitative Analysis ?

Yes! No! x

Q3 Chemistry | Qualitative AnalysisQ3 Single Choice Single Choice Question x

00:59 Time spent overtime attempt

Question −

Cl2 + OH

−

→ Cl

+ ClO

integer coefficients ?

− 3

­ when this equation is balanced with the smallest . What is the coefficient for OH​

6 2 4 3

Explanation −

3Cl2 + 6OH

−

→ 5Cl

+ ClO

− 3

+ 3H2 O

Key Concept

Wet tests for acid radicals : Salt or mixture is treated with dil. H2SO4 and also with conc. H2SO4 separately and by observing the types of gases evolved. Confirmatory tests of anions are performed.

Observation with dilute H2SO4 Observation Acid Radical Brisk effervescence with

Confirmatory Test Gas truns lime water milky but milkyness disappears on passing gas increases.

Na2 CO3 + H2 SO4 → Na2 SO4 + H2 O + CO2

Ca(OH) CO CaCO http://www.embibe.com/engineering/practice/solve/jee/chemistry/inorganic­chemistry/qualitative­analysis/session

H O

3/9

1/4/2016

evolution of colourless and odourless gas.

Embibe 2−

CO3

(Carbonate)

Ca(OH)

+

2

CO2

→

CaCO3

Lime water

CaCO3

+

+

H2 O

Milky

H2 O

+

CO2

Ca(HCO3 )

−→ −

2

​

Soluble

Add KI and starch solution blue colour.

Brown fumes

−

NO2 (Nitrite)

2NaNO3 + H2 SO4

−→ −

Na2 SO4 + 2HNO2

HNO2

−→ −

NO (Colourless)

2NaNO3 + H2 SO4

−→ −

Na2 SO4 + 2HNO2

HNO2

−→ −

NO (Colourless)

2NO + O2 (Air)

−→ −

2NO2 (Brown)

2KI + H2 SO4 + 2NHO2

−→ −

K2 SO4 + 2H2 O + 2NO + I2

I2 + Starch

−→ −

Blue colour

Gas turns lead acetate paper black.

Sodium carbonate extract (SE)* + Sodium nitroprusside ­ Purple colour Smell of rotten gas (H2S smell) on heating

Na2 S + H2 SO4

2−

S

H2 S

(Sulphide)

+

⟶H

2

S + Na2 SO4

(CH 3 COO) Pb 2

−→ −

PbS

2CH 3 COOH

+

(Black)

Na2 S

+

Na2 [Fe(CN) NO] 5

−→ −

Na4 [Fe(CN) NOS] 5

Sodium

(Purple)

nitroprusside 2−

Colourless gas with pungent smell of burning sulphur

Gas turns acidified K2Cr2O7 solution green [Different from CO3 ] since gas also tunrs lime water milky 2−

SO3

Δ

− Na2 SO3 + H2 SO4 −→ Na2 SO4 + H2 O + SO2

(Sulphite)

Cr 2 O

2− 7

+

3SO2

+

2H

+

−→ −

2Cr

3+

+

2−

3SO4

+

H2 O

(Green)

Solution gives smell of vinegar

⟶ Blood red colour

Aq. solution + Neutral FeCl3 CH 3 COO

−

(Acetate)

3CH 3 COONa

+

FeCl3

−→ −

Fe(CH 3 COO)

Neutral Aq. solution + AgNO3

White or yellowish white turbidity on warming.

Na2 S2 O3 2−

S2 O3

+

3

+

3NaCl

Red

⟶ White ppt. changing to black on warming

2AgNO3

−→ −

Ag S2 O3 2

+

2NaNO3

White ppt.

(Thiosulphate)

Ag S2 O3 2

+

H2 O

−→ −

Ag S + H2 SO4 2 Black ppt

Observation with concentrated H2SO4 http://www.embibe.com/engineering/practice/solve/jee/chemistry/inorganic­chemistry/qualitative­analysis/session

4/9

1/4/2016

Embibe

Observation

Acid radical

Colourless pungent gas involving while fumes with Aq. NH4​ OH

Cl

−

(Chloride)

Confiramatory Test Add MnO2 in the same test tube and heat­pale green Cl2 gas (i) S.E + HNO3 + AgNO3 solution ­ White ppt. soluble in Aq. NH3 (ii) Chrmoyl chloride Test (iii) Add Mn2O and Heat ­ Yellowish brown Br2 gas (iv)

Raddish brown fumes

Violet pungent vapours turning starch paper blue.

−

Br

−

I

(Bromide)

(Iodide)

S.E + HNO3 + AgNO3 solution ­ Pale yellow ppt. partially soluble in aq. NH3 (v) ​ayer test (vi) L S.E + HNO3 + AgNO3 ⟶ Yellow ppt. insoluble in aq. NH3 (vii) Layer test (vi)

Brown pungent fumes intensified by the addition of Cu turnings.

−

NO3 (Nitrate)

Ring test (viii) Acidified KMnO4 solution is decolorised (ix)

Colourless gas turning lime water milky and burning with blue flame.

2−

C2 O4

(Oxalate)

S. E + CH3COOH + CaCl2 white ppt. decolorising acidified KMnO4 solution (x).

ALUMINIUM 1.Add Nessler's Reagent to salt solution.

RESULT: Purple precipitate appears.

2.Add Sodium Hydroxide solution to salt solution.

RESULT: White precipitate appears. It dissolves in excess Sodium Hydroxide solution.

3.Add 2 ml of Sodium Hydroxide solution to salt solution and add Aluminon reagent.

RESULT: Reddish precipitate appears AMMONIUM 1.Add salt solution with a few drops of Nessler's solution and excess amount of Sodium Hydroxide.

RESULT: Brown precipitate appears.

2.Add salt with Sodium Hydroxide and heat it.

RESULT: Gas with smell of Ammonia comes. It turns Red litmus into Blue and gives white fume with glass bar, soaked in Conc. Hydrochloric acid.

ANTIMONY Add 5 ml of diluted HCl to salt. Pass H2S.Precipitate appears. Dissolve it by adding diluted HCl. To it add KOH and Bromine water. Add solid NH4Cl and boil for a few minutes. Filter it and add diluted HCl. Pass H2S. RESULT: Orange colour precipitate appears.

ARSENIC http://www.embibe.com/engineering/practice/solve/jee/chemistry/inorganic­chemistry/qualitative­analysis/session

5/9

1/4/2016

Embibe

Add pure Zinc and diluted H2SO4 to an arsenic compound. Cover the mouth of the test tube with filter paper soaked in AgNO3.

RESULT: The paper first turns Yellow and then black.

BARIUM 1.Add 5 ml of HCl to Salt. Add NH4OH and NH4Cl.Add strong solution of Ammonium carbonate. Boil and filter.

Precipitate appears. Add hot dil Acetic acid and add K2CrO4 solution.

RESULT: Yellow precipitate appears.

Dissolve it in HCl. Add S2S2 solution.

RESULT: White precipitate appears.

BISMUTH Add 5 ml of diluted HCl to salt. Pass H2S.Precipitate appears. Boil it with 5 ml of diluted Nitric acid. Add 5ml of Conc. H2SO4. Add Thio Urea.

RESULT: Yellow colour precipitate appears.

CADMIUM Add 5 ml of diluted HCl. Pass H2S.Precipitate appears. Boil it with 5ml of diluted Nitric acid .Add 5 ml of Conc.H2SO4. Add Ammonium Hydroxide.

RESULT: Yellow precipitate appears.

CALCIUM 1.Add salt solution and 2 ml of Potassium Chromate solution.

RESULT: No precipitate.

2.Add salt solution and 1 ml of Ammonium chloride and 1 ml of Ammonium Hydroxide and 2 ml of Ammonium oxalate.

RESULT: White precipitate appears. It does not dissolves in Acetic acid.

CARBONATE Add a few ml of diluted HCl to a little substance in a test tube.

RESULT: Brisk effervescence. Colourless,odourless gas turning lime water milky.

CHROMIUM Add 5 ml of diluted HCl to salt. Add NH4Cl. Precipitate appears. Boil it with Sodium Peroxide. Precipitate dissolves. Add acetic acid and lead acetate.

RESULT: Yellow precipitate appears.

COBALT 1.Add 5ml of dil HCl to salt and boil it. Add 1ml of Amyl alcohol ether and 1 ml of NH4CNS solution. Shake well.

RESULT: The upper layer is colour edintense blue.

http://www.embibe.com/engineering/practice/solve/jee/chemistry/inorganic­chemistry/qualitative­analysis/session

6/9

1/4/2016

Embibe

2.Add 5 ml of HCl to salt. Boil it .Add 2 ml of ZnSO4 solution. Soak a roll of filter paper and burn the wet end.

RESULT: The ash will be green.

COPPER 1.Add Ammonium Hydroxide solution .Then light blue precipitate appears. Add excess Ammonium Hydroxide.

RESULT: It will become dark blue.

2.Add 2 ml of Potassium Fluoride to salt solution.

RESULT: Chocolate brown colour precipitate appears.

FERRIC 1.Add 2 ml of Potassium Ferro cyanide to salt solution.

RESULT: Blue precipitate appears.

2.Add 2ml of Ammonium Thio cyanide solution to salt solution.

RESULT: Bloddish red appears.

FERRUS Add Pottassium Ferri cyanide to the salt solution RESULT: Blue precipitate appears LEAD 1.Add 2 ml of Potassium Chromate to salt solution.

RESULT: Yellow precipitate appears.

2.Add 2 ml of Potassium Iodide solution.

RESULT: Yellow precipitate appears. This becomes glittering gold particle when hot water is added and cooled.

MANGANESE Add 5 ml of diluted HCl to salt. Add NH4Cl .Precipitate appears. Add Benz dine and acid.

RESULT: The precipitate turns Blue.

MERCURY 1.Add 5 ml of Hydrochloric acid to little substance. RESULT: Precipitate appears.

Boil the precipitate with water. It does not dissolves. Add Sodium Hydroxide solution. Heat it and filter.

RESULT: Black precipitate appears.

2.Add 5 ml of diluted Hydrochloride acid to salt solution. Pass Hydrogen Sulphide gas. Precipitate appears. Boil it with 5 ml of diluted Nitric acid and the filter. In one portion add SnCl2 .

RESULT: White precipitate turns grey.

To other portion add KI RESULT: Red precipitate appears. http://www.embibe.com/engineering/practice/solve/jee/chemistry/inorganic­chemistry/qualitative­analysis/session

7/9

1/4/2016

Embibe

NICKEL Add HCl to the salt. Boil it. Add NH4Cl,NH4OH and K3Fe(CN)4 to a few drops.

RESULT: Yellowish brown precipitate soluble in NH4OH. SILVER 1.Add 5ml of HCl. to a little substance. Precipitate appears. Boil the precipitate with water. It does not dissolves.

Add Ammonium Hydroxide solution to it.

RESULT: The precipitate dissolves.

Add diluted Nitric acid RESULT: Curdy White precipitate appears.

STRANTIUM Add 5 ml of Hydrochloric acid to salt. Add Ammonium Hydroxide and Ammonium Chloride. Add strong solution of Ammonium Carbonate. Precipitate appears. Dissolve it in hot acetic acid. Add K2CrO4 solution. Filter it. Boil with Ammonium Sulphate solution.

RESULT: White precipitate appears.

TIN Add 5 ml of n diluted HCl to salt. Pass H2S. Precipitate appears. Dissolve it by adding diluted HCl. Add KOH and Bromine water until the colour of the liquid remains yellow. Add solid NH4OH and boil for a few minutes.White precipitate appears . Reduce by boiling with iron fillings, Filter and add HgCl. RESULT: White precipitate appears.

ZINC 1.Add Sodium Hydroxide solution to salt solution.

RESULT: White precipitate appears.

2.Add 2 ml of Potassium Ferro Cyanide solution.

RESULT: White precipitate appears. It dissolves in Sodium Hydroxide solution.

Add Your Notes

Rate This Question Too Easy Just Right Too Hard Bookmark x

00:59 http://www.embibe.com/engineering/practice/solve/jee/chemistry/inorganic­chemistry/qualitative­analysis/session

8/9