AIM: Analyse systematically the given salt of inorganic compound for anion and cation (by dry and wet test).
Test for Acidic Radicals
|
S.No. |
Treatment |
Observation |
Inference |
|
1 |
Mixture + dil. H2SO4 + |
Colourless, odourless gas with brisk effervescence |
Week acidic group present CO32- may be |
|
2 |
Confirmatory test Pass the above gas in lime water |
Lime water turns milky |
CO32- is confirmed |
|
Pass the above gas in lime water for longer time |
Lime water again turn to colourless solution |
CO32- is confirmed |
Test for Basic Radicals
|
S.No. |
Treatment |
Observation |
Inference |
|
1 |
Mixture + NaOH solution + Heat |
no smell of ammonia |
Zero group absent |
|
2 |
Original solution + dil HCl |
No ppt is formed |
1st group absent |
|
3 |
Pass H2S gas in above solution |
No ppt is formed |
2nd group absent |
|
4 |
Boil the above solution for off the H2S gas | ||
|
5 |
Bring a filter paper dipped in lead acetate on the mouth of test tube |
Filter paper not turn black |
H2s gas is escaped. |
|
6 |
The above solution+ conc. HNO3+ boil + cool + solid NH4Cl + NH4OH in excess |
No ppt. is formed |
3rd group absent |
|
7 |
Pass H2S gas in above solution |
No ppt. is formed |
4th group absent |
|
8 |
Filterate of 4th group Boil the above solution off H2S gas | ||
|
Bring a filter paper dipped in lead acetate solution |
Filter paper not turn black |
H2S gas excaped | |
|
9 |
Above solution +NH4OH + (NH4)2CO3 solution |
White ppt. is formed |
5th group present Ba2+, Sr2+, Ca2+ may be |
|
10 |
The white ppt. dessolve in acetic acid solution and divide into three parts | ||
|
1st part + K2CrO4 |
No yellow ppt is obtained |
Ba2+ is absent | |
|
2nd part + (NH4)2SO4 |
No white ppt is obtained |
Sr2+ is present | |
|
3rd part + (NH4)2C2O4 |
White ppt is obtained |
Ca2+ is present | |
|
11 |
Dry Test Dippted the platinum wire in dil. HCl and ignite it with ppt. |
Brick like flame is obtained |
Ca2+ is present |
Result : The above given mixture contains anion CO32- and cation Ca2+ are present.