## Search found 149 matches

Sat May 01, 2021 7:02 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

Computation of pH of 0.050 L C6H15N and HCl mixture, ICEchart.png (7.4 KiB) Viewed 52 times
Using Handerson HasselBalch equation,

pH = pKa + log (cB/cA) , where c= concentration, B= base, A=acid

we get pH= 10.72 + log(1)= 10.72
Fri Apr 30, 2021 3:15 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

Yes. My pH computation at the midpoint for C6H15N + HCl reaction was wrong. Now, after working some more computations, at the mid-point, my answer for pH of 0.075mL mixture of HCl and C6H15N is 6.1.

Fri Apr 30, 2021 12:34 am
Forum: Chemistry forum
Topic: Acid-Base Titrations
Replies: 3
Views: 87

### Re: Acid-Base Titrations

Actually i don't understand the meaning of 10% ionized (colorless) to 90% ionized(yellow).

I am working on this question. I want to read some chemistry articles on this topic and want to view some videos, if available on this topic.
Fri Apr 30, 2021 12:10 am
Forum: Chemistry forum
Topic: Acid-Base Titrations
Replies: 3
Views: 87

### Acid-Base Titrations

The indicator dinitrophenol is an acid with a $$K_a$$ of 1.1 × 10⁻⁴. In a 1.0 × 10⁻⁴ solution, it is colorless in acid and yellow in base.

Calculate the pH range over which it goes from 10% ionized (colorless) to 90% ionized (yellow).
Thu Apr 29, 2021 10:28 pm
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

So, my corrected answer to c)

At the beginning, the pH of 50 mL solution of C6H15N(triethyamine) is 10.72
At the mid-point, pH of 0.075 mL mixture of C6H15N and HCl is 10.72

At the equivalence point, pH of 0.100 mL solution of 0.1M C6H15N and 0.1 M HCl is 6.01.
Wed Apr 28, 2021 11:59 pm
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

Trifluoroacetic acid is a strong organic acid with pKa =0 My answer to c) At the beginning, the pH of 50 mL C6H15N is 7.49. At the midpoint, pH of 0.075 mL mixture of HCl and C6H15N will be log(0.025/0.075)=1.48 At the equivalence point, pH will be less than 7. Note: Kb of C6H15N= 5.3e-4 Is this ans...
Wed Apr 28, 2021 8:23 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

Thanks, you are correct. I wrongly computed the new volume after adding NaOH. I corrected my last post . You may check it now. Is my answer to b) is correct now?
Wed Apr 28, 2021 6:55 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

My answer to b) At the beginning, pH of the solution, before adding any amount of NaOH is 1.15(pH=-log(0.0707)=1.15). After adding 0.0025 mol of NaOH, to the 50 mL of CF3COOH, at the mid point, the pH of the solution is 1.48(pH=-log(0.0025/0.075)=1.48). At the equivalence point, pH will be 7 Is this...
Wed Apr 28, 2021 1:04 am
Forum: Chemistry forum
Topic: Definition of equivalent weight
Replies: 1
Views: 64

### Definition of equivalent weight

1)equivalent : an equivalent of an acid is the mass of acid required to provide one mole of hydrogen ions in a reaction; an equivalent of a base is the mass of base required to react with one mole of hydrogen ions. An equivalent of an oxidizing agent or of a reducing agent is the mass of the agent t...
Wed Apr 28, 2021 12:39 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

Answer to a) At the beginning, pH of the solution, before adding any amount of NaOH, is 1(pH=-log(0.1 )=1). After adding 0.0025 moles of NaOH to 50.0 mL of HCl, at the mid-point, the pH will be 1.48(pH=-log(0.0025/0.0525)=1.32). At the equivalence point pH will be 7. Is this answer correct? Is the t...
Tue Apr 27, 2021 8:36 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Re: Titration and pH computation

Thanks for pointing out my mistake. I corrected my mistake in my post. What would be indicator for the reaction in a) Will it be Phenol red?
Tue Apr 27, 2021 5:53 am
Forum: Chemistry forum
Topic: Titration and pH computation
Replies: 17
Views: 272

### Titration and pH computation

Calculate the pH at the beginning, at the midpoint, and at the equivalence point for the titration also choose an indicator: a) of 50 mL of 0.1M HCl with 0.1 M NaOH b) of 50 mL of 0.1 M CF3COOH with 0.1 M NaOH c) 50 mL of 0.1 M triethylamine with 0.1 M HCl I am working on these questions. My answer ...
Sat Apr 24, 2021 1:27 am
Forum: Chemistry forum
Topic: Molarity, weight %, Molality and other variables of solution
Replies: 3
Views: 117

### Re: Molarity, weight %, Molality and other variables of solution

Thanks for your correct answers to questions (a), (b), (c) and(d). My Computation work for answers to question (e) and (f). My answer to (e) P_{CCl_4}=0.981 \times 100 mm=98.1 mm, P_{CCl_4}= Vapor pressure of solution My answer to (f) \Delta T_{bp}=K_{bp}\times m; m= \frac{\Delta T_{bp}}{K_b}=\frac{...
Fri Apr 23, 2021 10:28 am
Forum: Chemistry forum
Topic: Molarity, weight %, Molality and other variables of solution
Replies: 3
Views: 117

### Molarity, weight %, Molality and other variables of solution

A solution is prepared by 10 g of solid para-dichlorobenzene (C6H4Cl2) in enough carbon tetrachloride to make a total of 350 mL of solution. The density of the resulting solution is 1.60 g/mL . (a) Compute the molarity of the solution. (b) Compute the weight % para-dichlorobenzene of the solution. (...
Fri Apr 23, 2021 9:24 am
Forum: Chemistry forum
Topic: Finding out unknown compound in the solution and boiling point of the solution
Replies: 7
Views: 142

### Re: Finding out unknown compound in the solution and boiling point of the solution

I think computed boiling point of the solution 81.255℃ is correct.