PRECIPITATION BY NaC2H3O2(aq)
(a) Add 2 mL of sodium acetate solution to the test tube.
(b) If a white precipitate forms at the bottom of the test tube, decant the remaining liquid into another clean test tube and retain the precipitate. (Decanting is the same as pouring, but clicking the "decant" option instead of entering an amount). Proceed to step 3 using the test tube containing decanted liquid.
(c) If no white precipitate forms, proceed to step 3.
3. PRECIPITATION BY NaCl(aq)
(a) To a test tube that contains only liquid and no precipitate, add 2 mL of sodium chloride solution.
(b) If a white precipitate forms at the bottom of the test tube, decant the remaining liquid into another clean test tube and retain the precipitate. (Decanting is the same as pouring, but clicking the "decant" option instead of entering an amount). Proceed to step 4 using the test tube containing decanted liquid.
(c) If no white precipitate forms, proceed to step 4.
4. PRECIPITATION BY Na2SO4(aq)
(a) To a test tube that contains only liquid and no precipitate, add 2 mL of sodium sulfate solution.
(b) If a white precipitate forms at the bottom of the test tube, decant the remaining liquid into another clean test tube and retain the precipitate. (Decanting is the same as pouring, but clicking the "decant" option instead of entering an amount). Proceed to step 5.
(c) If no white precipitate forms, proceed to step 5.
2. Write the net ionic equations for the formation of the three possible precipitates formed in steps 2, 3 and 4.
3. Explain how you could use flame tests to verify identity of the precipitates formed in each step.
This is not a question. It is a set of lab experiment instructions you should have followed. You need to perform the experiment and document your own results.
To determine the possible precipitates formed in steps 2, 3, and 4, we need to understand the reactions involved. Precipitation occurs when two aqueous solutions are combined, resulting in the formation of an insoluble solid (precipitate) and a liquid solution.
In step 2, we add sodium acetate solution (NaC2H3O2) to the test tube. Sodium acetate is a salt formed from the reaction between acetic acid (HC2H3O2) and sodium hydroxide (NaOH). The possible precipitate formed in this step is sodium acetate itself (NaC2H3O2).
In step 3, if no white precipitate forms in step 2, we proceed to add sodium chloride solution (NaCl) to the test tube. The possible precipitate formed in this step is sodium chloride (NaCl).
In step 4, if no white precipitate forms in step 3, we add sodium sulfate solution (Na2SO4) to the test tube. The possible precipitate formed in this step is sodium sulfate (Na2SO4).
Now, let's write the net ionic equations for the formation of these precipitates:
2. Net ionic equation for the formation of sodium acetate precipitate:
Na+(aq) + C2H3O2-(aq) → NaC2H3O2(s)
Net ionic equation for the formation of sodium chloride precipitate:
Na+(aq) + Cl-(aq) → NaCl(s)
Net ionic equation for the formation of sodium sulfate precipitate:
Na+(aq) + SO42-(aq) → Na2SO4(s)
To verify the identity of the precipitates formed in each step, flame tests can be conducted. Flame tests are used to identify the presence of certain metal ions in a compound by observing the characteristic color emitted by the metal ion when heated in a flame.
To perform a flame test, you would need a clean platinum or nichrome wire loop. Dip the wire loop into the precipitate solution obtained from each step (decanted liquid with the retained precipitate), making sure to remove any excess liquid. Then, hold the wire loop in the flame of a Bunsen burner.
If the precipitate contains a metal ion that emits a characteristic color, it will be observed as a flame color. For example, sodium ions (Na+) give a yellow-orange flame color. By comparing the flame color observed from the precipitates in each step to known flame test colors, you can verify the presence of the specific metal ions associated with the precipitates formed.