It is required to titrate ethanol solution .Being available a 0.2mol/l potassium dichromate solution and 4mol/l sulfuric acid solution on the presence of a convenient indicator.
a)indicate the glassware used for titration.
b)give a brief description of the procedure followed .How do we detect the equivalence point?
c)write the half reaction and the equation of the overall redox reaction.
d)the titration of 10ml of aqueous ethanal solution required 15ml of dichromate solution to reach the equivalence point .
Calculate the molar concentration in g/l of ethanol solution.
e)50ml of ethanal solution we heated with an excess of an ammonical silver nitrate solution.
I)write the half reaction and the equation of the overall reaction.
II)what mass of solid is formed due to the reaction?
THANK YOU FOR YOUR HELP!
abc<small>abc</small>
<font size="4">size 4</font>
<font size="2">size 2</font>
<pre>
abc
def ghi
jkl
</pre>
normalbold
a) The glassware used for titration typically includes a burette, a conical flask, and a pipette.
b) The procedure for titration involves the following steps:
1. Measure a specific volume of the ethanol solution (in this case, 10 mL) using a pipette and transfer it into a conical flask.
2. Add a few drops of a suitable indicator to the conical flask. In this case, a convenient indicator is not specified, so you may want to use phenolphthalein or bromothymol blue.
3. Fill a burette with the potassium dichromate solution.
4. Add sulfuric acid solution gradually to the conical flask. The sulfuric acid acts as a catalyst and helps in the reaction between ethanol and potassium dichromate.
5. Slowly add the potassium dichromate solution from the burette to the conical flask with constant swirling until a color change occurs, indicating the endpoint. The color change should correspond to the indicator used.
6. Note the volume of potassium dichromate solution consumed at the endpoint (in this case, 15 mL).
7. Repeat the titration process at least three times to ensure accuracy and consistency.
8. Calculate the molar concentration of the ethanol solution using the stoichiometry of the reaction and the volume of potassium dichromate solution consumed.
c) The half reactions and overall redox reaction for this titration can be determined based on the balanced chemical equation. Assuming that ethanol is oxidized by potassium dichromate, the half reactions and overall redox reaction can be written as follows:
Half reaction: C2H5OH(aq) -> CH3COOH(aq) + 4H+(aq) + 4e-
Overall redox reaction: 3C2H5OH(aq) + K2Cr2O7(aq) + 8H2SO4(aq) -> 3CH3COOH(aq) + Cr2(SO4)3(aq) + K2SO4(aq) + 7H2O(l)
d) To calculate the molar concentration of the ethanol solution, use the following formula:
Molar concentration (mol/L) = (volume of potassium dichromate solution × molar concentration of potassium dichromate) / volume of ethanol solution
Substituting the given values:
Molar concentration (mol/L) = (15 mL × 0.2 mol/L) / 10 mL
Molar concentration (mol/L) = 0.3 mol/L
Since the density of ethanol is approximately 0.790 g/mL, we can convert the molar concentration to grams per liter (g/L):
Molar concentration (g/L) = 0.3 mol/L × 46.07 g/mol
Molar concentration (g/L) = 13.82 g/L
Therefore, the molar concentration of the ethanol solution is approximately 13.82 g/L.
e) I) The half reaction for the reaction of ethanal (acetaldehyde) with ammonical silver nitrate can be written as follows:
CH3CHO(aq) + Ag(NH3)2+(aq) -> CH3COO-(aq) + Ag(s) + 2NH4+(aq)
The overall reaction combines the half reaction with the relevant stoichiometry.
II) To calculate the mass of solid formed due to the reaction, you need to know the molar mass of Ag. Given that the reaction involves a 1:1 stoichiometric ratio between Ag and CH3CHO, the molar mass of Ag can be used.
Mass of solid formed = moles of Ag × molar mass of Ag
To calculate the moles of Ag, use the stoichiometry from the balanced equation and the volume of ethanal solution:
Moles of Ag = (volume of ethanal solution × molar concentration of ethanal) / 1000 mL/L
Substitute the given values and calculate the mass of solid formed.