## Finding out pH of the solution

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Dhamnekar Winod
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### Finding out pH of the solution

6.00 g acetic acid and 10.00 g sodium acetate are dissolved in enough water to make 1 L of solution.

a.What is the pH of the solution?
b.If 5 mL of 0.1 M HCl are added to the solution, what is the new pH?
c.If instead 5 mL of 1.0 M KOH are added to the original solution, what is the new pH?

I am working on these questions.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
Dhamnekar Winod
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Posts: 149
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay],Maharashtra State,India

### Re: Finding out pH of the solution

$$pK_a$$ for Ethanoic acid =4.77,$$pH= 4.77 + log(\frac{0.122 M }{0.1 M })=4.85$$
Last edited by Dhamnekar Winod on Sat Apr 10, 2021 3:20 am, edited 3 times in total.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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### Re: Finding out pH of the solution

The chemical reaction is wrong. Its only a mixture of acetic acid and sodium acetate. There is no reaction. You forget the lightning on the right side. Leftside you have a negative charge what gives thunder storm on the right side.
On the other hand the calculation of pH is correct because you consider the mixture.
Read about buffer solution in your text book or internet. This is relevant for b and c.
Dhamnekar Winod
Sr. Staff Member
Posts: 149
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay],Maharashtra State,India

### Re: Finding out pH of the solution

Yes. Chemical reaction was wrongly written by me. Thanks for pointing out my mistake. I have corrected the chemical reaction now. is that correct?
Last edited by Dhamnekar Winod on Fri Apr 09, 2021 9:25 pm, edited 1 time in total.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

### Re: Finding out pH of the solution

Dhamnekar Winod
Sr. Staff Member
Posts: 149
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay],Maharashtra State,India

### Re: Finding out pH of the solution

$$pH = 4.77 + log (\frac{0.1215}{0.1005})=4.85$$

Last edited by Dhamnekar Winod on Sat Apr 10, 2021 3:17 am, edited 1 time in total.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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Location: Berlin, Germany

### Re: Finding out pH of the solution

Yes correct
Dhamnekar Winod
Sr. Staff Member
Posts: 149
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay],Maharashtra State,India

### Re: Finding out pH of the solution

Handerson-Hasselbalch equation = pKa + log ([conjugate base]/ [weak acid])

pH =pKa + log ([A⁻][HA]) ,

Hence, pH= 4.74 + log ( 0.127/0.095)= 4.84

Original Concentration of Vinegar - added concentration of 0.005M KOH =0.1 M -0.005 M KOH = 0.095 M

Original concentration of sodium acetate + added concentration of 0.005 KOH = 0.122 M + 0.005 M KOH = 0.127 M
Last edited by Dhamnekar Winod on Sat Apr 10, 2021 4:46 am, edited 3 times in total.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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Posts: 750
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Location: Berlin, Germany

### Re: Finding out pH of the solution

I dont know where you get the ml. Both acetic acid and sodium acetate are added as the mass. To get ml need specific gravity of 100% Acetic acid and sodium acetate is anyway a salt or need concentration before adding.