RIshi G. answered • 02/28/23
North Carolina State University Grad For Math and Science Tutoring
To determine the quantitative titration curve for the given reaction, we need to first write the balanced chemical equation:
NaClO + HCl → NaCl + H2O + Cl2
We know that the reaction between NaClO and HCl is a 1:1 reaction, which means that 1 mole of HCl reacts with 1 mole of NaClO.
The quantitative titration curve can be obtained by plotting the pH of the solution against the volume of HCl added. The pH will depend on the concentration of the HCl solution and the volume of NaClO being titrated.
At the initial point, before any HCl has been added, the pH of the solution will be the pH of the bleach solution. This value is not given in the problem, so we will assume it is 10 (which is typical for household bleach).
At the 1/2 equivalence point, half of the moles of NaClO will have reacted with HCl. This means that the number of moles of HCl added will be equal to half of the number of moles of NaClO present initially. Therefore, we can use the following equation to calculate the volume of HCl added:
moles HCl = 0.5 × moles NaClO
moles NaClO = (30.00 mL bleach) × (0.100 mol/L) × (1 L/1000 mL) = 0.003 mol NaClO
moles HCl = 0.5 × 0.003 mol NaClO = 0.0015 mol HCl
volume of HCl = (0.0015 mol HCl) / (0.100 mol/L) = 0.015 L = 15.00 mL
To calculate the pH at the 1/2 equivalence point, we need to use the Henderson-Hasselbalch equation:
pH = pKa + log([base]/[acid])
For the given reaction, the acid is HCl and the base is NaClO. The pKa of the hypochlorite ion (ClO-) is 7.5. At the 1/2 equivalence point, we have equal amounts of HCl and NaClO, which means that [base] = [acid]. Therefore, the pH can be calculated as:
pH = 7.5 + log(1) = 7.5
At the equivalence point, all of the NaClO has reacted with HCl. This means that the number of moles of HCl added will be equal to the number of moles of NaClO present initially. Therefore, we can use the following equation to calculate the volume of HCl added:
moles HCl = moles NaClO
moles NaClO = (30.00 mL bleach) × (0.100 mol/L) × (1 L/1000 mL) = 0.003 mol NaClO
moles HCl = 0.003 mol HCl
volume of HCl = (0.003 mol HCl) / (0.100 mol/L) = 0.030 L = 30.00 mL
At the equivalence point, all of the NaClO has reacted with HCl, which means that the pH of the solution will be determined by the hydrolysis of the resulting sodium chloride. The pH of a neutral solution (such as a solution of NaCl) is 7.
At the 1 over titration point, excess HCl has been added to the solution. This means that all of the NaClO has reacted, and there is excess HCl present in the solution. The pH of the solution will
To plot the entire quantitative titration curve, we would need to determine the pH values at various points between the initial point and the 1 over titration point, taking into account the amount of HCl added at each point. This could be done by calculating the moles of HCl added and the moles of NaClO remaining at each point and using the Henderson-Hasselbalch equation to calculate the pH.
However, without additional information about the pH of the bleach solution and the exact endpoint of the titration, it is difficult to determine the shape of the quantitative titration curve between the initial point and the 1 over titration point.
In general, the shape of a quantitative titration curve for the titration of a weak base with a strong acid is characterized by an initial slow rise in pH, followed by a more rapid rise in pH as the equivalence point is approached, and a final leveling off of pH at the endpoint, which occurs when excess acid has been added.
However, the shape of the curve can be influenced by a number of factors, including the strength of the acid and base being titrated, the initial concentration of the base, and the presence of any buffering agents in the solution. In this case, we do not have enough information about the bleach solution or the endpoint of the titration to make any specific predictions about the shape of the quantitative titration curve.
