2.7: Common qualitative analysis reagents, their effects, and hazards
|
Reagent |
Effects |
Hazards |
|---|---|---|
|
6M Ammonia (\(\ce{NH4OH}\) or \(\ce{NH3}\)) |
increases [\(\ce{NH3}\)], increases [\(\ce{OH^-}\)], decrease [\(\ce{H3O^+}\)], precipitates insoluble hydroxides, forms \(\ce{NH3}\) complexes |
Toxic, corrosive, and irritant |
|
6M Hydrochloric acid (\(\ce{HCl}\)) |
increases [\(\ce{H3O^+}\)], increases [\(\ce{Cl^-}\)], decreases [\(\ce{OH^-}\)], dissolves insoluble carbonates, chromates, hydroxides, some sulfates, destroys hydroxo and \(\ce{NH3}\) complexes, and precipitates insoluble chlorides |
Toxic and corrosive |
|
3% Hydrogen peroxide (\(\ce{H2O2}\)) |
Oxidizing agent in acidic medium, reducing agent in basic medium |
corrosive |
|
6M Nitric acid (\(\ce{HNO3}\)) |
Increases [\(\ce{H3O^+}\)], decreases [\(\ce{OH^-}\)], dissolves insoluble carbonates, chromates, and hydroxides, dissolves insoluble sulfides by oxidizing sulfide ion, destroys hydroxo and ammonia complexes, good oxidizing agent when hot |
Toxic, corrosive, and strong oxidant |
|
3M Potassium hydroxide (\(\ce{KOH}\)) |
Increases [\(\ce{OH^-}\)], decreases [\(\ce{H3O^+}\)], forms hydroxo complexes, precipitates insoluble hydroxides |
Toxic and corrosive |
|
1M Thioacetamide (\(\ce{CH3C(S)NH2}\)) |
Produces \(\ce{H2S}\), i.e., a source of sulfide ion (\(\ce{S^{2-}}\)), precipitates insoluble sulfides |
Toxic and carcinogen |