pH and [H+] conversion

@ pH 7
--> [H+] = 100 nmol/L

@ pH 7.36
--> [H+] = 44 nmol/L

@ pH 7.4
--> [H+] = 40 nmol/L

@ pH 7.44
--> [H+] = 36 nmol/L

Rule

1. For every 0.3 change in pH,
   --> [H+] changes by a factor of 2
2. For every 1.0 change in pH
   --> [H+] changes by a factor of 10

 

Thus,

--> Almost all [H+] at all pHs can be estimated

For example,

@ pH 7.1
[H+] = 80 nmol/L (40x2)

@ pH 6.8
[H+] = 160 nmol/L (80x2)

@ pH 7.3
[H+] = 50 nmol/L (100/2)

 

Thus, it can be estimated

(bracket contains real value using calculator)

 

6 - 1000 (1000)

6.1 - 800 (794.3)

6.2 - 640 (630.93)

6.3 - 500 (501.19)

6.4 - 400 (398.11)

6.5 - 320 (316.23)

6.6 - 250 (251.19)

6.7 - 200 (199.53)

6.8 - 160 (158.49)

6.9 - 125 (125.89)

7.0 - 100 (100)

7.1 - 80 (79.43)

7.2 - 62.5 (63.1)

7.3 - 50 (50.12)

7.4 - 40 (39.81)

7.5 - 31.25 (31.62)

7.6 - 25 (25.12)

7.7 - 20 (19.95)

7.8 - 15.675 (15.85)

7.9 - 12.5 (12.59)

8 - 10 (10)