sigfigs for acids/bases

[005199302]

I know Dr. Lavelle mentioned this in class, but what are the sigfig rules for pH/pOH? Also, is there any situation where we disregard this rule?

[Mindy Kim 4C]

I believe Dr. Lavelle said in lecture that however many sigfigs are in the molarity of H+ or OH- is how many decimal places there should be in your pH or pOH value.

[Jocelyne Milke 1G]

also sig figs for pH count after the decimal.

[Kyither Min 2K]

For pH, the significant figures matter AFTER the decimal. So if the concentration of Hydronium ions is .0136 mol/L , 3 sig figs. The pH would be 1.866, 3 sig figs after the decimal.