A solution of Ba(OH)2 is titrated into a solution of HOBr.
(i) Calculate the volume of 0.115 M Ba(OH)2(aq) needed to reach the equivalence point when
titrated into a 65.0 mL sample of 0.146 M HOBr(aq).
(ii) Indicate whether the pH at the equivalence point is less than 7, equal to 7, or greater than
A solution of Ba(OH)2 is titrated into a solution of HOBr.
(i) Calculate the volume of 0.115 M Ba(OH)2(aq) needed to reach the equivalence point when
titrated into a 65.0 mL sample of 0.146 M HOBr(aq).
(ii) Indicate whether the pH at the equivalence point is less than 7, equal to 7, or greater than
2 answers
We can start by writing the balanced chemical equation for the reaction between Ba(OH)2 and HOBr:
Ba(OH)2 + 2 HOBr → Ba(Br)2 + 2 H2O
From the equation, we can see that the stoichiometry of the reaction is 1:2 between Ba(OH)2 and HOBr. This means that for each mole of Ba(OH)2 used, we will need 2 moles of HOBr.
(i) To find the volume of Ba(OH)2 we need, we can use the following equation:
n(HOBr) = C(HOBr) x V(HOBr)
where n is the number of moles of HOBr, C is the concentration of HOBr, and V is the volume of HOBr used. We can rearrange this equation to solve for V:
V(HOBr) = n(HOBr) / C(HOBr)
We know that at the equivalence point, the number of moles of Ba(OH)2 added will be equal to the number of moles of HOBr present in the sample. Since we have 65.0 mL of 0.146 M HOBr, we can calculate the number of moles of HOBr:
n(HOBr) = C(HOBr) x V(HOBr) = 0.146 mol/L x 0.0650 L = 0.00949 mol
Therefore, at the equivalence point, we will need half as many moles (0.00475 mol) of Ba(OH)2. The concentration of Ba(OH)2 is given as 0.115 M, so we can find the volume of Ba(OH)2 needed using the same equation as before:
V(Ba(OH)2) = n(Ba(OH)2) / C(Ba(OH)2) = 0.00475 mol / 0.115 mol/L = 0.0413 L = 41.3 mL
So we need 41.3 mL of 0.115 M Ba(OH)2 to reach the equivalence point.
(ii) At the equivalence point, all the HOBr will have reacted with the Ba(OH)2 to form a salt (Ba(Br)2) and water. Since HOBr is a weak acid and Ba(OH)2 is a strong base, the pH at the equivalence point will be greater than 7 (basic).
Ba(OH)2 + 2 HOBr → Ba(Br)2 + 2 H2O
From the equation, we can see that the stoichiometry of the reaction is 1:2 between Ba(OH)2 and HOBr. This means that for each mole of Ba(OH)2 used, we will need 2 moles of HOBr.
(i) To find the volume of Ba(OH)2 we need, we can use the following equation:
n(HOBr) = C(HOBr) x V(HOBr)
where n is the number of moles of HOBr, C is the concentration of HOBr, and V is the volume of HOBr used. We can rearrange this equation to solve for V:
V(HOBr) = n(HOBr) / C(HOBr)
We know that at the equivalence point, the number of moles of Ba(OH)2 added will be equal to the number of moles of HOBr present in the sample. Since we have 65.0 mL of 0.146 M HOBr, we can calculate the number of moles of HOBr:
n(HOBr) = C(HOBr) x V(HOBr) = 0.146 mol/L x 0.0650 L = 0.00949 mol
Therefore, at the equivalence point, we will need half as many moles (0.00475 mol) of Ba(OH)2. The concentration of Ba(OH)2 is given as 0.115 M, so we can find the volume of Ba(OH)2 needed using the same equation as before:
V(Ba(OH)2) = n(Ba(OH)2) / C(Ba(OH)2) = 0.00475 mol / 0.115 mol/L = 0.0413 L = 41.3 mL
So we need 41.3 mL of 0.115 M Ba(OH)2 to reach the equivalence point.
(ii) At the equivalence point, all the HOBr will have reacted with the Ba(OH)2 to form a salt (Ba(Br)2) and water. Since HOBr is a weak acid and Ba(OH)2 is a strong base, the pH at the equivalence point will be greater than 7 (basic).
3 answers