1) Neutralization is a chemical reaction in which an acid and a base react to form a salt and water. The reaction involves the transfer of H+ ions from the acid to the OH- ions from the base.
The equation for the neutralization of HCI (hydrochloric acid) by NaOH (sodium hydroxide) is:
HCl + NaOH -> NaCl + H2O
2) The pH of a solution is a measure of its acidity or alkalinity. The H+ ion concentration can be calculated using the formula: H+ ion concentration = 10^(-pH)
In this case, if the pH of orange juice is 3.35, then the H+ ion concentration can be calculated as:
H+ ion concentration = 10^(-3.35)
3) Titration is a laboratory technique used to determine the concentration of a substance in a solution by reacting it with a solution of known concentration. It involves the gradual addition of a solution of known concentration (titrant) to a solution of unknown concentration (analyte) until the reaction between the two is complete.
It is important to rinse the burette and pipette with the solution they will eventually contain to ensure that there are no contaminants or residual substances that could potentially affect the accuracy of the titration results.
4) The balanced equation for the reaction is:
H2SO4 (aq) + 2NaOH (aq) -> Na2SO4 (aq) + 2H2O (l)
From the balanced equation, it can be seen that 2 moles of NaOH react with 1 mole of H2SO4.
Given that the concentration of H2SO4 is 0.500 mol/L and the volume used is 1250 mL (or 1.25 L), the moles of H2SO4 can be calculated as:
moles of H2SO4 = concentration x volume = 0.500 mol/L x 1.25 L = 0.625 moles
Since the stoichiometric ratio between H2SO4 and NaOH is 1:2, the moles of NaOH can be calculated as:
moles of NaOH = 0.625 moles x (2 moles NaOH / 1 mole H2SO4) = 1.25 moles
Therefore, the concentration of the sodium hydroxide solution is 1.25 mol/L.
5) The criteria for choosing an indicator in an acid-base titration are:
- The indicator should undergo a distinct color change at or near the equivalence point (the point at which stoichiometrically equivalent amounts of the acid and base have reacted).
- The color change should occur over a narrow pH range, so that the point of color change corresponds to the equivalence point.
- The indicator should not react with the analyte or titrant, as this could affect the accuracy of the results.
- The indicator should be added in small quantities, as excessive amounts can introduce errors in the titration.
1 What is neutralization? Write an equation for the neutralization of HCI by NaOH. 2 Calculate the H+ ion concentration of orange juice with pH = 3.35? 3 What is titration? Why is it important to rinse the burette and pipette with the solution they will eventually contain? 4 In an acid-base titration 50.0 mL of a solution of sodium hydroxide is neutralized by exactly 1250 mL of sulfunc acid of concentration 0.500 mol/L H2SO4 (aq) + 2NaOH (aq)-> Na2SO4 (aq) + 2H20 (1) What is the concentration, in moll, of the sodium hydroxide solution? 5 What is the criteria for choosing an indicator in acid-base titration?
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