Chemistry Test for Ions 1

7/26/2019 Chemistry Test for Ions 1

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Test for IonsTest for the positive ions Na+K+Ca+

Sr+Ba+Cu2+

ApparatusTake nichrome wire and and dip it with

concentrated HCl acid and bring it to the roaring

fame. Keep doing it until no colour is produced.

This is done to clean the nichrome wire and to

make sure that no other chemical Is present. Next

we will do ame test take the acid with nichrome

wire arain and dip with the unknown solid. Place the

nichrome wire in the roaring fame. !emember to

clean nichrome wire beore beore each experimentb" concentrated HCl acid#.

The resulting fame will produce di$erent colour

Na% K% Ca% &r% 'a% Cu(%

Nichrome

!oari

'unse)nknown

Flame

test is

applicable

for

Group

1 an

!roup

2

metal

s

inclu

in!

coppe

r

ions"


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*ellow+

orange

,ilac fame 'rick red

fame

!ed fame ,ight green

fame

'lue

fame

,ithum ions - red

&ulphur ions - blue Carbon ions - orange

Test for Transaction metal ionor transaction metal ion we can add &odium h"droxide to a unknown

transaction ion.


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Cu2+ Fe2+ Fe#+ $n2+

'lue prcipitate /reen precipitate

but become red+

brown upon

standing because

Iron II# h"droxide

gets oxidi0ed.

!ed+brown

precipitate

1hite precipitate


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N2T3+ Copper ions can be tested in either fame test wa" or precipitation

test.

Test for Ammonium ions4mmonium ions is dipped in sodium h"droxide.

It reacts with h"droxide to orm ammonia and water

4mmonia can be tested b" putting holding damp red litmus paper which

turns blue.

2rdip a glass rod into the concentratedHCi 5essel and dip it into the solution

and this will produce 4mmonium

chloride with white smoke that

con6rms 4mmonia is present.

Test for ne!ative ions

Carbonate ions C%#2&

Test- To either the solid7 or an a8ueous solution o the solid7 under test add

dilute h"drochloric acid.

It is best to use dilute nitric acid. &ome acid+carbonate combinations can

produce an insoluble salt that coats the solid carbonate and stops the

reaction7 but this doesn9t happen i "ou use nitric acid because all nitrates

are soluble.

!esult- This will or bubbles o gas carbon dioxide#. This gas will turn

limewater milk". Carbonate % acid salt % water % carbon dioxide


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Sulphate ions S%'2&

Test- To an a8ueous solution o the solid under test7 add dilute h"drochloric

acid ollowed b" a ew drops o barium chloride solution.

!esult- This will orm a white precipitate o barium sulphate#.

Test for (alie Ions4pparatus

)nknown &olid is taken )nknown &olid is

:isssol5ed in 1ater

:ilute Nitric acid is

added to to remo5e

an" Impurities in orderto gi5e a clear result.


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Then 4dd ew drops o 48ueous &il5er

Nitrate and &il5er halides precipitate will

orm which gi5es di$erent colours or

di$erent Halide ions.


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Chlorine Cl&


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Bromine Br&


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Ioine I&


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)roblems

4::

:ilute 48ueous 4mmonia dissol5e &il5er chloride but not sil5er bromide

'ut concentrated 48ueous 4mmonia will dissol5e both &il5er chloride and

&il5er bromide


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'ut

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Chemistry Test for Ions 1