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8/8/2019 chem pro kv

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performed the experiment on

STUDY OF CONSTITUENTS OF ALLOYS

as part of her Chemistry investigatory

Project under my supervision.

Mr.A.K.Jha

K.V no.1,

Gandhinagar.


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It gives me great pleasure & deep

satisfaction in presenting this

Chemistry Project.

I take this opportunity to be

thankful to several people withwhose help & encouragement , I

have completed this project

successfully.

I would like to thank Mr.A.K.Jha

for his able guidance, valuable

suggestions & continuous

encouragement during the time of

the performance of the project.


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I also wish to put my deepest

sense of appreciation & thanks to

Mr.Deepak Singh . His motivation

helped me to work productively &

efficiently.

I am very grateful to my parents

for

their constant & loving support.

Finally, there are some special

people without whose support

this project would have never

come

to fruition whose name might

not appear in this formal

acknowledgement.


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Devanshi N.Vyas

INTRODUCTion

An alloy is a homogenous mixture of

two or more metals or a metal & a

non metal. An alloy of mercury with

another metal is called an amalgam.

Most familiar metals are not of very


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When elements are mixed to make

an alloy, the metallic element present

in the largest amount by weight is

called the parent metal & the others

are the alloying agents. The alloying

agents are dissolved in the parent

metal but do not combine chemicallywith it. Instead, they also arrange

themselves in a regular pattern filling

the spaces between the atoms of the

parent metal without disturbing itsbasic atomic structure.

APPLICATION OF

ALLOYS

IN


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MODERN SOCIETY

Alloys have become an indispensiblepart of our daily life. Historically,

alloys have played an extremely vital

role in the development of civilization

as we see it today (The Bronze Agebeing the most vital among these).

They have penetrated into all sections

of our life & have changed the face of

modern society in a unique manner.

An alloy can be made to match a

predetermined set of characteristics

for a specific purpose. This is very

useful in designs of rockets,spacecraft

& supersonic aircrafts.

Alloys of heat-resistance metals like

tantalum, niobium, tungsten ,cobalt &

nickel & lightweight ones like


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aluminium & titanium have been

developed specially for these

purposes. Alloys of boron, hafnium,

zirconium find use in nuclear reactors

& niobium-tin in semiconductors &

nickel in desalination plants.Alloys have applications ineveryday life too. Utensils in thekitchen , machinery & tools inindustry, transport facilities...the

list is endless. After a few cuts , theblade of an ordinary iron knife losesits edge & becomes dull. Now take aknife made of stainless steel (justadding 10-20% chromium) & see how

long it lasts!

In the field of medicine, alloys havebecome indispensible. From fillings tobraces on ones teeth, the dentist

uses alloys. Every prosthetic(artificial)


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implant consists of strong &lightweight alloys.

Thus, in small but extremelysignificant ways, alloys arerevolutionizing our society byproviding economical & effectivealternatives to pure metals.

Some common alloys:

Alloy CompositionBrass Copper

Zinc50-90%20-40%

Bronze CopperTin

60-90%5-35%

Gunmetal

CopperZinc

85-90%1-3%

Tin 8-12%

Alloys are generally made to serve the

following purposes :

To modify chemical reactivity:


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aluminium has beautiful golden

colour.

To resist corrosion : Iron gets

rusted & corroded. Its corrosion

takes place with time but stainless

steel which is an alloy of iron &

carbon does not get rusted.

Alloys are prepared from the

metals by the techniques of fusion,

compression or simultaneous

electrodeposition. The complete

analysis, the components of the

alloy are found out & in

quantitative analysis their

percentage composition is

determined. In the present project

we will carry out qualitative

analysis only.


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OBJECTIVE

To analyse a given sample of alloy

& to identify the presence of metal

ions in it by qualitative analysis.

REQUIREMENTS

China dish, test-tubes, funnel,

filter paper, common laboratory

reagents, tripod stand, burner,

glass rod, tongs, test tube stand,

conc.HNO3, conc. HCl, all

chemicals used in salt analysis.


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THEORY

A small piece of brass is dissolved

in 50% HNO3 when metals gets

converted to their nitrates. After

the removal of excess nitric acid,

the solution is tested for Cu+2 &

Zn+2 ions.

4Zn + 10HNO3

4Zn(NO3)2 +N2O +5H2O

3Cu + 8 HNO3

3Cu(NO3)2+4H2O+2NO

The sample of Indian coin & solder

wire is decomposed using aqua

regia & then tested for the

presence of Pb+2

,Sn+2

,Cu+2

& Fe+3

.


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PROCEDURE

For brass:

Place a small piece of brass in a

china dish & heat this with

minimum quantity of 50%HNO3

so as to dissolve the piece

completely.

Continue heating the solution

till a dry solid residue is

obtained.

Dissolve solid residue in dil.HCl

& filter .Add distilled water to

the filtrate.


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Pass H2S gas through the

filtrate. A black precipitate of

copper sulphide is obtained.

Separate the black ppt. & keep

the filtrate for the test of Zn+2

ions. Dissolve black ppt by

heating it with 50% HNO3. Tothis solution add ammonium

hydroxide solution. Appearance

of deep blue colour in solution

shows the presence of copperions in the solution.

To test for Zn+2 ions, boil the

filtrate to remove H2S gas, then

add solid NH4Cl to this & heat todissolve NH4Cl.Add excess of

NH4OH so that the solution is

ammoniacal. Now pass H2S gas

through it. Dirty white or grey


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If the alloy remains partially

undissolved , dissolve the alloy

again in 20 ml aqua regia(15 mlconc.hydrochloric acid & 5 ml

conc. Nitric acid).

Heat in the fume chamber until

the alloy dissolves completely.

Evaporate to dryness on a water

bath very carefully.

Add 5 ml. of conc. Hydrochloric

acid to solution, heat & dilute with

15 ml water. Cool & filter.

Perform the systematic

procedure of basic radical

detection, with the various wet

tests according to the scheme(as

outlined below).


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1.substance under

analysis:SOLDER WIRE

Solubility : soluble in conc.nitric

acid

Observation : Yellowish solution

Obtained


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Experiment

Observtions Inference

Group I:

Add a fewdrops of dil.HClto 2 ml of soln.

White ppt of PbS

is obtained.

Pb+2

indicated.

ConfirmatoryTest:1.Add a few mlof K2CrO4 to sol

2.Add a few mlof KI to soln.

Yellow ppt of

PbCrO4 obtained.Yellow ppt ofPbI2 obtained.

Pb+2

confirmed.Pb+2

confirmed.

Group II :Pass H2S gasthrough soln ofgroup 1.ConfirmatoryTest :Add a few ml ofHgCl2 to soln

Brown pptobtained.

Grey ppt of Hgobtained

Sn+2

indicated.

Sn+2

confirmed.

Group III:To 2 ml of solnadd a pinch ofNH4Cl & excessNH4OH.

No precipitation. Group IIIabsent

Group IV:To soln ofgroup 3 passH2S gas

No precipitation. Group IVabsent


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Pass H2S gasthrough soln ofgroup 1.

Confirmatory Test:1.Add a few dropsof K4Fe(CN)6 tosolution.2.Add NH4OH inexcess to solution.

A black ppt isobtained.

A chocolate-brown ppt isobtained.A bluesolution is

obtained.

Cu+2indicated.

Cu+2

confirmed.

Cu+2

confirmed.Group III:To 2 ml of soln adda pinch of NH4Cl&excess NH4OH.

A reddishbrown ppt isobtained.

Fe+3indicated.

Confirmatory Test:

1.Add a few ml ofK4Fe(CN)6 tosolution.2.Add a few dropsof KCNS to soln.

Solution turnsPrussian blue.

A blood redcolouration isobserved.

Fe+3

confirmed.

Fe+3

confirmed.

Group IV:To soln of group 3pass H2S gas

Noprecipitation. Group IVabsent

RESULT


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The constituents detected in the

alloys were:

1.Brass: copper & zinc

2.Solder:lead & tin

3.Coin: copper & iron

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