Answer:
a. The phenolphthalein acts as a color changing indicator to signal the endpoint of the reaction.
Explanation:
Phenolphthalein is an organic substance with chemical formula 
.
It is a substance commonly used in acid-base titrations to indicate the end point in the titration because phenolphthalein is colorless in acidic solutions but turns a purplish-pink color in basic solutions.
In this way it helps visually to notice when the final point of the titration has been reached.
An element’s atomic number is equal to the number of protons in that element’s nucleus. The mass number is the total number of an atom’s protons and neutrons. Protons have a positive charge; electrons have a negative charge; and neutrons are electrically neutral.
Putting it all together, given that the atomic number of lead is 82, the number of protons a lead atom contains is 82. The number of neutrons would be the difference between 207 and 82, or 125 neutrons. Finally, since you have a neutral atom, there must be an equal number of electrons as the number of protons—that is, 82 electrons.
Thus, you’ve got 82 protons, 125 neutrons, and 82 electrons.
Answer:
The resulting structure is:
R-CH-CH2 (OH)-CH-CH2(OH)-CH-CH2(OH)-CH-...
Explanation:
It can be said that vinyl alcohol cannot be polymerized by addition polymerization, since a very unstable radical would be formed, which is not possible. Generally, it is formed by polymerization and subsequent hydrolysis of the vinyl polyacetate. According to the exercise, the structure that results with its four units can be seen that the hydroxyl groups are found in the methylene carbons
