# Finding pH given molarity and volume

by pmart491
Tags: molarity, volume
 P: 19 1. The problem statement, all variables and given/known data If you mix 200mL of a 1.8M HCl solution with 300mL of a 1.16M NaOH solution, what will be the pH of the solution? 3. The attempt at a solution Well im really lost with this problem. Im pretty sure you need to convert each to moles. .2L HCl x 1.8moles HCl ------------------ 1L HCl .3L NaOH x 1.16 moles NaOH --------------------------- 1L NaOH HCl=.36moles NaOH=.348moles HCl + NaOH -> NaCl + H2O not too sure where u go from there
 HW Helper P: 2,692 The acid and the base react 1:1, so which is in excess, and by how much?
 P: 19 is it .36-.348=.012 moles of HCl which = number of H+ ions? pH=-log(.012) = 1.92?
P: 19

## Finding pH given molarity and volume

or do u have to change moles of HCl back to molarity?

.012moles HCl
-------------
.5L total

=.024

pH=-log(.024)=1.62
 HW Helper P: 2,692 HCl in aqueous solution is strongly ionized, or completely ionized for most practical purposes. For pH, you want the hydrogen ion CONCENTRATION AS MOLARITY...., and then find the negative logarithm.
 P: 19 yea so itd be 1.62 right?
 Admin P: 22,352 Yep, 1.62 it is.
 Sci Advisor HW Helper PF Gold P: 3,725 Welcome back, Borek! You were missed.