# Finding pH

#### Helly

No, why should it be?

But I think this is beyond high school chemistry.
Only left Na2CO3 right? All HCl become NaCl salt?
Na2CO3 is salt? Doesnt react with water?
Or react with water become 2NaOH +CO2?

#### studiot

Only left Na2CO3 right? All HCl become NaCl salt?
Na2CO3 is salt? Doesnt react with water?
Or react with water become 2NaOH +CO2?
Yes the carbonate will be in excess.

What values of concentrations did you calculate ?

The carbonate ion reacts with water to form a bicarbonate ion and a hydroxyl ion.

$$\displaystyle CO_3^{2 - } + {H_2}O \to HCO_3^ - + O{H^ - }$$

The important thing here is the hydroxyl ion.

This will make the solution alkaline.

I don't know if you can do the calculation but the pH will be about 11.5

For your purposes the exact value may not matter since it is so far different.

topsquark and Helly

#### studiot

The answer is B>C>A. How to find [H] for them ?
I agree with this.

Now it is possible to reason this out without actually calculating the pH values for each, using only High School knowledge.

Calculating the values is University/College level stuff.

I don't know where you are so which answer do you want?

#### Helly

I agree with this.

Now it is possible to reason this out without actually calculating the pH values for each, using only High School knowledge.

Calculating the values is University/College level stuff.

I don't know where you are so which answer do you want?
I think i got hasselbalch equation.
I finished the question. B>C>A

#### studiot

I think i got hasselbalch equation.
I finished the question. B>C>A
Yes Henderson-Hasselbalch equation is one way.
I was going to ask if you understood Kb = 2.1 x 10^-4 for sodium carbonate.

You are interested in Chemistry
And you are intelligent.
It is really useful to know what you you could and could not follow or understand in order to give better answers.

The more you put in, the more you will get out.

Helly

#### Helly

Yes Henderson-Hasselbalch equation is one way.
I was going to ask if you understood Kb = 2.1 x 10^-4 for sodium carbonate.

You are interested in Chemistry
And you are intelligent.
It is really useful to know what you you could and could not follow or understand in order to give better answers.

The more you put in, the more you will get out.
Kb is attribute of salts only or also weak base or weak base only?
Do chemist memorize kb of each salts?

#### studiot

No Chemists look them up in tables such as Kaye and Layby or Lange or CRC handbook if they are old fashioned.

More modern kiddies like you use Google, PubChem and so on

You may find this slide useful.