[yanna.banana]

Solving for pH and concentration A 1L flask has 2x10^-2 M HCl mixed with 2X10^-2 NaOH. Solve for pH and concentration?

So i started with balancing the equations and found that the species in equilibrium would be [H3O+],[Na+],[OH-],[Cl-]
I used the Kw = 10^-14 = [H3O+][OH-]
I rearranged this equation to be [OH-]=Kw/[H3O+] because I saw that in class but I am not sure as to why I am doing that.
and I already know that [Na+] and [Cl-] have 2x10^-2 (concentrations? am I right?)
but then i am not sure of the next steps.
Any pointers or explanations would be greatly appreciated.

[AWK]

Solving for pH and concentration A 1L flask has 2x10^-2 M HCl mixed with 2X10^-2 NaOH. Solve for pH and concentration?

Be more precise. When mixing volumes are important!
If you want to calculate nearly exact pH of 0.02 M NaCl you need activity coefficients.

[yanna.banana]

Hey sorry if i am not being clear,
all the question says is
2 x 10-2 moles of hydrochloric acid are placed in three flasks of 1 liter. The first flask up to volume with distilled water; They are added to the second 2 x 10-2 moles of NaOH and the third 3 x 10-2 moles NaOH before make up to volume with distilled water. What is the pH and concentrations of all species at equilibrium in each of the flasks ?.

[AWK]

This sounds quite different. So you have 3 problems
1. Diluted strong acid
2. Diluted salt
3. Diluted an excess of NaOH
All problems are quite elementary and can be solved even without calculator.

[yanna.banana]

can you explain how to me?

[AWK]

1.
0.02 mole of HCl in 1 liter. What is concentration? Strong or weak? What is concentration of H+ (or H₃O+)? What is pH?