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I want to know the Acid and basic radial detection test chart. Like for acid it is  1)...

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mayank6169 | eNotes Newbie

Posted July 5, 2013 at 8:55 AM via web

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I want to know the Acid and basic radial detection test chart. Like for acid it is 

1) with dil.h2so4 , if we get brisk effervesence then it is co3-

2) with conc. h2so4 , for cl we get pungent smell 

for br- we get brown gas ..and for no3-, I- etc ... 

Same I want know about basic test. Can anybody hep me ? 

 

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llltkl | College Teacher | Valedictorian

Posted July 5, 2013 at 11:13 AM (Answer #1)

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It all depends upon the range of basic radicals you are supposed to detect. Unlike acid radicals where interference is less common, basic radicals exhibit a lot of interference in their detection tests and hence an exhaustive ‘this for that’ type of test schedule is not available. Some radicals do respond to certain test, some do not, while some may respond in absence of certain other radicals. Therefore, the scheme is to divide total analysis in several preliminary stages before going into the grind of exhaustive systematic analysis that involves bunching the range of cations into analytical groups first, followed by actual characterizations. However, when the list is small, chances of interference is negligible and a few diagnostic tests can be designed. Some examples of preliminary diagnostic tests for basic radicals are as follows:

Flame test: (soak a little salt in conc. HCl and hold it near the base of the nonluminous Bunsen flame):

Flame colour         Basic radical

Golden yellow          Na+

Greenish blue           Cu2+

Grass green              Ba2+

Crimson red              Sr2+

Violet                         K+

Similarly tests for Fe2+, Cu2+ and Ni2+ are as follows:

a) Add potassium ferrocyanide solution to dilute HCl solution of the salt, if a deep blue precipitate appears, it indicates Fe2+.

b) Add potassium ferrocyanide solution to dilute acetic acid solution of the salt, if a chocolate brown precipitate appears, it indicates Cu2+ radical

c) Add dimethyl glyoxime solution to a dilute HCl solution of the salt, then add excess NH4OH, a rose red precipitate indicates presence of Ni2+ radical.

The list is endless and has to be modified according to convenience and scope.

Sources:

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