# PH solution

n=C*V = 2*10-4*350= 0.07mol

Borek
Mentor
OK, now how many moles of NaOH will react with 0.07 moles of H+? Do you know what the reaction is? Reaction equation?

2 NaOH + H2SO4 ---> Na2SO4 + 2 H2O

Borek
Mentor
This reaction is correct, but it is not what I am asking about.

Ahhh i don't know that one

Borek
Mentor
Can you write NaOH in dissociated form?

sure
NaOH ----> Na+ + OH-

Borek
Mentor
OK, now, what would happen when you add H+ to the mix?

H+ + Na+ + OH- -> ???

i dont know...but why we will add H+

Borek
Mentor
Why? Because the question is about reaction between H+ and OH-. You have a solution of H+ and you add solution of OH- (Na+ and SO42- don't take part in the reaction, they are so called spectators).

What simple, electrically neutral molecule can be a product of reaction between H+ and OH-? Try to guess, it is so simple you will hate yourself you have not realized it earlier.

sulphuric has 2 protons.

so ph =-log(0.0004)

=-(log4-4)
=-(0.6021-4)
=3.3979

1 hydrogen has 1 proton but in sulphuric there are 2 hydrogen

Borek
Mentor
sulphuric has 2 protons.

so ph =-log(0.0004)

=-(log4-4)
=-(0.6021-4)
=3.3979

And read forum rules, giving final answers is against them. Not to mention giving wrong final answers.

Hello Borek

CA*VA=CB*VB
2*10-4*350=mB/40
mB=2*10-4*350*40 = 2.8g

That's it ?

Borek
Mentor
2.8g of NaOH it is.

2.8g of NaOH it is.

Yay :tongue2: thank you Borek