ACIDS AND BASES (LAB)

Question 1

is a method of quantitative analysis for determining the concentration of an acid or base by exactly neutralizing it with a standard solution of base or acid having known concentration.

Answer 1

Acid-Base Titration

Question 1

is used to monitor the progress of the acid–base reaction.

Answer 1

pH indicator

Question 2

solution of known concentration

Answer 2

Titrant

Question 3

solution of unknown concentration

Answer 3

Analyte

Question 4

2 types of acid-base titration:

Answer 4

Indicator-based titration
Potentiometric Titration

Question 5

the indicator changes color at the equivalence point

Answer 5

Indicator-based titration

Question 6

is colorless in acidic solutions and pink in basic solutions.

Answer 6

Phenolphthalein

Question 7

red in acidic solutions and yellow in basic solutions

Answer 7

Methyl orange

Question 8

pH of the solution is monitored using a pH meter

Answer 8

Potentiometric Titration

Question 9

: is the process by which our bodies convert food into energy

Answer 9

Metabolism

Question 10

: use to maintain the pH of the blood. It consists of carbonic acid (H2CO3) and bicarbonate ion (HCO3-).

Answer 10

Bicarbonate buffer system

Question 11

DIFFERENT TYPES OF BUFFERS

Answer 11

Bicarbonate buffer system
Protein buffer system
Nucleic acid buffer system

Question 12

to measure the acidity or alkalinity of water, which is important for ensuring that water is safe to drink and use.

Answer 12

Water quality testing

Question 13

: to measure the acidity of food and beverages, which is important for ensuring that they have the correct flavor and shelf life.

Answer 13

Food and beverage analysis

Question 14

: to detect the presence of tyrosine or tryptophan, which are aromatic amino acids. The test reagent is a solution of mercury(II) nitrate and concentrated nitric acid. When the test reagent is added to a protein that contains tyrosine or tryptophan, a red precipitate is formed.

Answer 14

Millon’s test

Question 15

to detect the presence of the amino acid, tryptophan. The test reagent is concentrated nitric acid. When the test reagent is added to a protein that contains tryptophan, a yellow precipitate is formed.

Answer 15

Xanthoproteic test

Question 16

to detect the presence of the amino acid, tyrosine. The test reagent is a solution of concentrated hydrochloric acid and sodium nitroprusside. When the test reagent is added to a protein that contains tyrosine, a purple-red ring forms at the interface of the two solutions.

Answer 16

Hopkins-Cole test

Question 17

to detect the presence of peptide bonds, which are linkages between amino acids. The test reagent is a solution of copper(II) sulfate and sodium hydroxide. When the test reagent is added to a protein, a purple color forms.

Answer 17

Biuret test

Question 18

to detect the presence of amino acids. The test reagent is a solution of ninhydrin in concentrated sulfuric acid. When the test reagent is added to a protein, a purple color forms.

Answer 18

Ninhydrin test:

Question 19

: The test reagent is a solution of a metallic salt, such as lead acetate or mercuric chloride. When the test reagent is added to a protein, a white precipitate may form.

Answer 19

Precipitation by metallic salts:

Question 20

The test reagent is a solution of an alkaloidal reagent, such as tannic acid or picric acid. When the test reagent is added to a protein, a white precipitate may form.

Answer 20

Precipitation by alkaloidal reagents:

Question 21

This test is used to detect the presence of the amino acid, cysteine. The test reagent is a solution of ferric chloride. When the test reagent is added to a protein that contains cysteine, a blue color forms.

Answer 21

Heller’s test

Question 22

This is a process by which proteins are precipitated from solution by the addition of a salt, such as ammonium sulfate. The salt disrupts the interactions between the water molecules and the protein molecules, causing the protein molecules to aggregate and precipitate.

Answer 22

Salting out

Question 23

This is a process by which proteins are denatured and precipitated by heat or by the addition of an acid or base. The denaturation of proteins disrupts the structure of the protein molecules, causing them to aggregate and precipitate

Answer 23

Coagulation test