This is an example in my book. I have the answer for it, but I don't know why my answer was wrong. Here's the question: Lauren pours 40 mL of .1M NaOH into 100 mL of Megan's .1 M HCl. What is the pH? Here's what I did: R NaOH+HCl ⇔ NaCl + H2O I .004 , .01 ⇔ 0 0 C -.004 , -.004 ⇔ +.004 , +.004 E 0 , .006 ⇔ .004 , .004Then, I made another RICE table for the remaining HCl: R HCl + H2 O ⇔ H3O++ Cl- I .006 C -.006 -.006 +.006 +.006So then pH=-log(.006/.14)=3.14 But my teacher's book says pH=1.37. UPDATE: I was using WolframAlpha.com to calculate the log and apparently it calls log what I would call ln. When I entered log base 10 (.006/.14) everything worked out fine. If somebody knows how, delete this post please.