titration buffers lab report

BismiAllah hir Rahman nir Raheem

Titration

Describe , in general , what affect the addition of acid has on the pH

of the 1 M , 0 .75 M , 0 .5 M and 0 .25 M solutions of sodium carbonate

Acid neutralizes buffer . As concentration of acid increased , pH decreased of the buffering solution . Hence , it is noticed that 1M sodium carbonate is much stronger buffer as compared to 0 .75 , 0 .5M and 0 .25M In IM solution more acid was needed to neutralize the buffer . However as gradually as less powerful buffer 0

.25 M was neutralized much faster as it was weak buffer

4 ) What is the most effective buffering range of the various sodium carbonate solutions

Effective buffering range is between 1M and 0 .75M

5 ) Which of the sodium carbonate solutions is the best buffer ? Which is the poorest buffer ? Why

IM is most strong and best buffer and 0 .25M is most weak buffer . IM sodium carbonate has higher concentration of buffer that can resist change in pH while 0 .25M has less concentration of buffer and that 's why it is weak and poor buffer

6 ) Determine the pKa value from the titration curves (Hint 1 : You may need to find the definition for pKa before you can determine it . Hint 2 There are 2 pKa values found in this titration . Determine the pKa found in the acidic pH range only . Does the starting concentration of the sodium carbonate solution affect the determination of the pKa value Why

[n 6th question .u really didn 't show me the calculation and titartion curve . what valuse u used of ka .i dont really get it . include all the caluclations and ur titration curve show me clearly]

pKa stands for acid dissociation constant in a pH solution

pKa -log10 Ka

pH pKa log [HA] /[A]

pH Pka (when acid is 50 dissociated

There are 2 pKa values

The pKa value of first part is 26

The pKa value of second part 18

Yes starting concentration of sodium carbonate will affect determination of pka value because it depends on buffering concentration and acidity As soon as acidity is increased it neutralizes buffer . A stronger buffer will have its pH close to pKa value while weak buffer will have its pH far from pKa value

Titration Curve 1

HCl (ml ) pH

1 11 .15

2 11

3 10 .65

4 10 .45

5 10 .35

6 10 .25

7 10 .15

8 10 .00

9 10 .00

10 9 .90

11 9 .80

12 9 .70

13 9 .65

14 9 .55

15 9 .43

16 9 .35

17 9 .30

18 9 .22

19 9 .18

20 9 .12

21 9 .05

22 9 .0

23 8 .91

24 8 .87

25 8 .79

26 8 .70

27 8 .60

28 8 .50

29 8 .40

30 8 .20

31 8 .01

32 7 .75

33 7 .30

34 7 .08

35 6 .90

36 6 .70

37 6...