Consider 57.5 mL of a solution of weak acid HA (Ka = 1.00 10-6), which has a pH of 3.800. What volume of water must be added to make the pH = 6.000?

i made a ka for both of them to find out HA

and i got

.025M for fhte first one

and 1E-6M for the second one is that wrong?

andt hen i did M1V1=M2V2 and got the wrong answer!

please help!