Answer to Question #183182 in General Chemistry for dafd

Question

Titration Lab

Titrant: NaOH

Analyte: HCl

Question-->

Find pH at HALF-WAY point

Find Volume at HALF-WAY point

Find pH at EQUIVALENCE POINT

Find Volume at EQUIVALENCE POINT

Given data: Volume 0.10 M HCl used (mL)-->8.00

Volume 0.10 M NaOH added (mL)

0.00

0.00

1.00

1.50

2.50

3.50

4.00

4.50

5.00

5.25

5.50

5.75

6.75

7.00

8.00

8.50

9.00

10.00

10.50

11.00

11.30

11.60

11.80

12.20

12.60

13.00

13.50

14.00

14.10

16.10

18.10

20.30

21.30

22.10

26.10

27.10

pH

0.81

0.83

0.88

0.99

1.30

2.32

5.33

5.47

6.16

6.49

6.91

9.73

10.50

10.71

11.20

11.48

11.68

11.98

12.09

12.19

12.22

12.28

12.32

12.35

12.41

12.48

12.50

12.55

12.63

12.71

12.77

12.83

12.89

12.92

12.94

13.00

Answer 1

How can you find the pH at halfway titration? Answer: Halfway point just means that the moles of added acid = half of the moles of base (moles acid = (1/2)moles base). For weak bases, pOH=pKb (and pH=pKa for weak acids)

The half-equivalence point is halfway between the equivalence point and the origin. This is the point at which the pH of the solution is equal to the dissociation constant (pKa) of the acid.