Physics, asked by swasthik5556, 1 year ago

Conclusion about ph value

Answers

Answered by AĐÄRSĦ
5
The purpose of this lab was to determine the pH of several different salt solutions through the

use of acid-base indicators and then determining the value of the equilibrium constant for each.

The tables attached contain all the observations and calculations made during this lab. Table 2

shows the colors and pH transitions of indicators that were determined by me and my lab group.

Table 3, shows the colors of salt solution with different indicators which was done individually

and shows the pH level and concentrations of the salt solutions. Then next, table 4 shows which

of the salt solutions went through a hydrolysis reaction and which ions were spectators if there

were any. Then, based on my determination in table 4, table 5 shows the salt solutions that went

through the hydrolysis reaction and the dissociation constant expression for each as well as the

values of the k’s.

Bronsted-Lowry acids are species that donate the H

+

ion, while Bronsted-Lowry bases are

species that accept the H

+

ion. Some salts have acidic or basic properties when added to water

because they ionize with water to go through a process called hydrolysis. The magnitude of K

a

or

K

b

tells you that the primary species that is present in the aqueous salt solution at equilibrium is

mostly acidic, basic or neutral.

The primary source of error in this experiment is due to the adding of the indicators to the wells

and the possibility of some contamination and mixture of different salt solutions which would

alter the pH levels of each of the salt solutions when the indicator is added. How to minimize this

error could be thoroughly rinsing the well after each use and conducting multiple trials of

determining what the color of the salt solution is after adding the indicator. It is important to use

only a few drops of indicator when testing solutions is because at a certain point when the color

changes is half of the indicator is in acid form and the other half is in basic form and if you go

beyond that point the pH of the salt solution could be determined not accurately.

Because we are trying to abide by the 12 principles of green chemistry it was very important to

be precise and accurate when performing this experiment because the large amount of waste

produced and that is why multiple trials for the testing of each salt solution would not be

conducted.

Thus this experiment shows the importance of being precise and accurate as well as

calculating correctly to try and accomplish a true or accepted value of the pH and concentrations

of the salt solutions.

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