SODA LIME TEST FOR AMIDE NITROGEN if the organic compound is in the form of ___________________, heating it with _________ (NaOHand CaO) will liberate ________________ gas (characteristic pungent ammonia odor)

1. amino nitrogen (–NH2) 2. soda lime 3. ammonia (NH3)

1. BEILSTEIN TEST 2. SILVER NITRATE TEST

Module 1: QUALITATIVE ANALYSIS OF ELEMENTS IN ORGANIC COMPOUNDS Flashcards by Aho Tei

the elements that can be commonly found among organic compounds include

C - chlorine
H - hydrogen
O - oxygen
N - nitrogen
S - sulfur
P - phosphorus
Si - silicon

F - fluorine
Cl - chlorine
Br - bromine
I - iodine

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“systemic approach” that can give satisfactory results in identifying elements in organic compounds using qualitative chemical reagents

Qualitative Analysis

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CO2 is detected by __________, while the H2O is detected by anhydrous cupric sulfate

lime water

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approach with the use of organs/senses (except hearing)

organoleptic approach

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upon heating, the carbon and hydrogen present in the organic compound are oxidized to ________________________

carbon dioxide and water

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CO2 reacts with Ca(OH)2 forming

CaCO3 and H2O

CO2 + Ca(OH)2 → CaCO3 + H2O

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these elements must be converted first into inorganic ions before proceeding to qualitative analysis → done by fusing the organic compound with the __________

sodium metal

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qualitative chemical tests highly rely on “organoleptic approach” through observation of test results

Qualitative Analysis

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REACTION WITH CUPRIC OXIDE

detected by strongly heating the said substance with _____________

cupric oxide (CuO)

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CO2 is detected by lime water, while the H2O is detected by ______________________

anhydrous cupric sulfate

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other elements such as “nitrogen, halogens, and sulfur” are “difficult to detect” in an organic compound → they __________ in solution and are “bonded covalently”

do not ionize

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CO2 reacts with Ca(OH)2 forming CaCO3 and H2O, wherein the _____________________ due to the formation of precipitates (CaCO3)

clear solution becomes turbid

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H2O reacts with anhydrous CuSO4 forming CuSO4 * 5 H2O, wherein the _______________ (CuSO4 * 5 H2O)

white powder turns to blue

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H2O reacts with anhydrous CuSO4 forming

CuSO4 * 5 H2O

5 H2O + CuSO4 → CuSO4 * 5 H2O

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the alkaline solution obtained by extracting the fused mass in water is called _____________

sodium extract or Lassaigne’s extract

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the following reactions are created upon the fusion of the said elements with sodium metal:

S + 2 Na → ?

Na2S

! aside from Lassaigne’s sodium fusion test, there are other applicable qualitative tests that can be used

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the following reactions are created upon the fusion of the said elements with sodium metal:

C + N + Na →

NaCN

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the following reactions are created upon the fusion of the said elements with sodium metal:

X (Cl, Br, I) + Na → ?

NaX (X = Cl, Br, I)
sodium halide

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SODA LIME TEST FOR AMIDE NITROGEN

if the organic compound is in the form of ___________________, heating it with _________ (NaOHand CaO) will liberate ________________ gas (characteristic pungent ammonia odor)

amino nitrogen (–NH2)
soda lime
ammonia (NH3)

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SODA LIME TEST FOR AMIDE NITROGEN

to confirm the presence of the said gas, a moist ________________________

red litmus paper must turn to blue

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SODA LIME TEST FOR AMIDE NITROGEN

the reaction involved:

urea + NaOH + CaO → ??

2 NH3 + Na2CO3

Note:
urea + NaOH + CaO → 2 NH3 + Na2CO3

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______________is limited to organic compounds with amino (–NH2) group only, nitro (-NO2) and azo (-N=N-) compounds cannot be detected by this test

soda lime test

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soda lime test is limited to organic compounds with _____________ , nitro (-NO2) and azo (-N=N-) compounds cannot be detected by this test

= amino (–NH2) group only

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Test for Halogens

BEILSTEIN TEST
SILVER NITRATE TEST

* an organic halogen compound dipped in a copper wire will yield (what color of flame when burned?)

green-colored flame

What elements are Halogens

fluorine chlorine bromine iodine

* the copper oxide from the "copper wire" formed upon heating, reacts with the halogen from the organic compound to form __________ which is responsible the color of the flame

cupric halide

_____________ does not yield a positive result (cupric fluoride is not volatile)

fluorine

SILVER NITRATE TEST * the halogen reacts with silver nitrate in the presence of ______________ forming insoluble silver halide

dilute nitric acid

SILVER NITRATE TEST * the halogen reacts with silver nitrate in the presence of dilute nitric acid forming ______________

insoluble silver halide

SILVER NITRATE TEST * the silver halide yields a (what precipitate?) ________________, confirming the presence of a halogen

white to light yellow precipitate

R-X + AgNO3 + HNO3 → ??

AgCl

Test for nitrogen

Soda lime test

Test for Sulfur

LEAD ACETATE TEST

LEAD ACETATE TEST * the organic compound containing sulfur will yield ____________ upon reaction with lead acetate

lead sulfide

LEAD ACETATE TEST * the presence of sulfur is identified by the production of (what color of precipitate?) _____________ through lead acetate test

brownish-black precipitate

_____________ contains the amino acid cysteine

albumin

albumin contains the amino acid _________ (an amino acid with sulfhydryl group)

cysteine

* in strongly basic solution, cysteine will react to lead ions (Pb2+) forming (what precipitate?) ________________

black precipitate, PbS

* __________ the solution causes the breaking of the polypeptide chain

heating

NaOH → Na+ + OH– 2 Na+ + S → Na2S → 2 Na+ + S2– S2– + Pb2+ → PbS

LEAD ACETATE TEST * chemical reaction involved

Test for oxygen

FERROX TEST

FERROX TEST * oxygen can be detected using ________________

ferrox paper or iron (III) hexathiocyanatoferrate

FERROX TEST * iron (III) ammonium sulfate reacts with potassium thiocyanate to form iron (III) hexathiocyanatoferrate

take note

FERROX TEST * this compound dissolves in the presence of oxygen giving off (what color?) _______________ of the solution

red to reddish-purple color

_____________ is prepared by soaking a filter paper in methanol with equal parts of ferric chloride and ammonium thiocyanate

ferrox paper

the complex FeSCN2+ yields a (what solution color?) ______________ as it is distributed through the filter paper and the organic compound containing oxygen

deep red colored solution

CARBON & HYDROGEN = Reaction with lime water

clear solution turns turbid

CARBON & HYDROGEN = Reaction with anhydrous cupric sulfate

white powder turns blue

NITROGEN = Soda lime test

characteristic pungent odor, red litmus turns blue

HALOGENS = Beilstein test

green-colored flame

SULFUR = Lead acetate test

formation of black precipitate

HALOGENS = Silver nitrate test

formation of white precipitate

OXYGEN = Ferrox test

turns to red to reddish-purple solution

Ca(OH)2 is _______

lime water

"nitrogen, halogens, and sulfur" must be converted first into inorganic ions before qualitative analysis (True or False) How is it done?

True : this is done by fusing the organic compound with the sodium metal

NaOH and CaO is ________

soda lime

Cannot be detected by soda lime test

= nitro (-NO2) = azo (-N=N-) compounds

iron (III) ammonium sulfate + potassium thiocyanate =??

iron (III) hexathiocyanatoferrate