Cheatography
https://cheatography.com
Lab Prep
Clean beakers and test tubes (make sure small test tubes). |
Grab strips of different colored washi tape for labeling. |
Grab disposable pipettes. |
Fill soap and distilled water. |
Separation of Quall II ions:
Separation of Qual II ions done with strong base, NaOH. |
Mn 2+, Ni2+, Fe2+. Will precipitate as a Hydroxides. |
Al3+ and Zn2+ will precipitate soluble Hydroxides. |
Add 2 mL of original solution to small cleaned test tube. (DO NOT USE 2 mL WHEN DOING UNKNOWN) |
Add 15 drop of 6M NaOH |
Centrifuge and save precipitate and supernate. (Test for incomplete reaction; several drops of 6 M NaOH) |
Label supernate "Al & Zn ions". |
Dissolve the precipitate with the minimum amount of concentrated Nitric Acid (HNO3) possible. |
If necessary heat the solution. |
Label dissolved, " Mn, Ni, & Fe ions" |
Testing for Mn 2+ Presence
Add approximatly 1/2 of "Mn, Ni, & Fe" to a small test tube. (DO NOT USE THAT MUCH IF DOING QUAL II UNKNOWN." |
Add solid NaBiO3 in excess to the solution and centrifuge. |
Deep purple solution confirms Mn 2+ ion presence. |
Testing for the presence of Fe 3+
Add remaining 1/2 solution of "Mn, Ni, & Fe" (DO NOT USE ALL IF DOING QUAL II UNKNOWN" |
Excess ammonia does not react with Mn the addition is to make Fe a brown precipitate and Ni a blue supernate. |
Add 5 drops of $M NH4Cl to the solution |
Add concentrated ammonium hydroxide (NH4OH) till it is basic to litmus. |
Add additional three drops to check for reaction completion. |
Centerfuge & save supernate label for Ni testing |
Dissolve percipitate with 6M HCl |
Add 5 drops of 0.1M NH4SCN. Presence of blood red color confirms presence of Fe. |
Testing for Ni Presence
Complexing agent (Dimethylglyoxime) reacting specifically with Ni ions |
Using test tube labeled Ni supernate |
Appearance of pinkish red precipitate. |
Testing for Al Presence
Addition of acid breaks down Al & Zn Hydroxides to ions |
Add HNO3 drop wise to supernated labeled "Zn & Al ions" solution must be basic to litmus paper. |
Add 5 more drops after that to insure reaction completion. |
Presence of white cloudy percipitate indicated presence of Al ions.` |
Centerfuge and save Zn supernate for analysis. |
Testing for Zn percipitate
Addition of 6M HCl to supernate Zn+ until solution is acidic to litmus paper |
Add 3 drop of 0.2M K4[Fe(CN)6] and stir. |
Centrifuge and discard supernate. |
Light green precipitate confirms presence of Zn. |
|
Created By
Metadata
Favourited By
Comments
No comments yet. Add yours below!
Add a Comment
Related Cheat Sheets