All Questions
Tagged with acid-base experimental-chemistry
124
questions
60
votes
4
answers
246k
views
Why add water first then acid?
From school, I remember a very important rule: first you need to pour the water and then the acid (when you need to mix them) not vice-versa. This is because otherwise the aсid becomes very hot and ...
- 1,053
22
votes
3
answers
3k
views
How was it concluded that the H3O+ rather than H+ is the "acid" ion?
I suspect that initially, scientists believed that the acid ion was $\ce{H^+}$ since $\ce{H2}$ is released through electrolysis, right? But what experiment was done to change the standpoint to assume ...
- 369
20
votes
2
answers
3k
views
Why is carbonic acid often ignored?
Water (distilled or not) picks up CO2 from the atmosphere, some of which dissolves to form carbonic acid (H2CO3), lowering the pH by a point or two.
From that it seems like carbonic acid would be the ...
- 1,172
18
votes
2
answers
23k
views
Why is a theoretical titration curve higher than a practical one?
I'm currently in high school and I did two titrations. The first one is a titration of $10.0~\mathrm{mL}$ $0.1~\mathrm{M}$ $\ce{HCl}$ with $x~\mathrm{mL}$ $\ce{NaOH}$. I obtained the following ...
- 307
17
votes
1
answer
10k
views
Neutralizing a sulfuric acid spill
From my AP Chem Prep Book:
What should you do if you spill sulfuric acid on the countertop?
A) Neutralize the acid with vinegar.
B) Sprinkle solid NaOH on the spill.
C) Neutralize the acid with ...
- 388
12
votes
3
answers
13k
views
Why isn't dry CaCl₂ used to dry HCl gas instead of concentrated sulfuric acid?
In our chemistry books, it is said that concentrated sulphuric acid is used to dry $\ce{HCl}$ gas.
But, concentrated sulphuric acid is a strong oxidising agent so, why isn't $\ce{HCl}$ gas oxidised ...
- 1,232
12
votes
1
answer
53k
views
How do I calculate the concentration of sulphuric acid by a titration experiment with sodium hydroxide?
In my latest chem lab the objective was to create a primary standard of $\ce{NaOH}$ and use it to determine the concentration of sulfuric acid.
The first part of the lab was determine the molarity of ...
- 333
10
votes
4
answers
8k
views
What is the real pKa of water?
What is the $\text{p}K_\text{a}$ of water? A simple google search yields the value $15.74$, but this site and this paper say it's $14.0$.
According to my understanding, the correct answer should be $...
- 601
9
votes
1
answer
1k
views
Questions about Buffer System (Lab)
I will be doing a lab on Hydrogen Phosphate buffer system tomorrow and I have a few questions about the buffer system. I am not sure if my assumptions are correct.
(1) What would happen to the rate ...
- 435
8
votes
2
answers
16k
views
Why, in titration, is universal indicator not commonly used?
My teacher said that we always used indicators such as methyl red, methyl orange, litmus, phenolphthalein, etc. rather than universal indicator. I don't understand why, though, would not universal ...
- 309
8
votes
2
answers
27k
views
Why are strong acids and bases not suitable as primary standards?
This is one of the questions with which I have puzzled over, and can arrive at no definite conclusion. Why are strong acids or bases, such as $\ce{H2SO4}$,$\ce{ HNO3}$, $\ce{HCl}$, and $\ce{NaOH}$ not ...
- 189
8
votes
1
answer
1k
views
The open circuit voltage of a battery: Does it decrease with increase in pH of electrolyte while the voltage across a load increase?
Why does the open circuit voltage of a battery decrease with increase in $\mathrm{pH}$ of electrolyte, but the voltage across a load increase?
I tested a cell which had aluminum sulfate as its anode ...
- 864
7
votes
2
answers
1k
views
Mechanism of the blue bottle experiment
I have researched multiple mechanisms for this experiment yet all of them suggest different versions or are too vague. None of them are consistent since the final overall equation seems to be missing ...
- 73
7
votes
2
answers
642
views
Question about the differences of white and grey NaH properties
We are having some problems with the next reaction in our lab. As you can see, is the sulfonylation of an indole in which we use NaH (60% dispersion in mineral oil) as a base. This reaction goes with ...
- 81
7
votes
0
answers
516
views
Does phosphoric acid remove stainless steel electropolished layer?
Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide.
Phosphoric acid is ...
- 2,205