Can you please check these sentences? I'm unsure about the use of synonyms. Thank you.

1)Dr Jekyll creates a potion capable to release (or of realising) his evil side.
2) For this purpose, he uses a particular salt, adds it to other componenents and brings them to the boil. Once the ebullition has subsided (I need a synonym), he drinks the potion.
3) First,he suffers horrible agonies but then he experiences a sense of freedom in his increased weakdness. His evil side has always been dominated by the good and is therefore much less exercised.
4) Once Hyde, his evil side, is released, he achieves domination over (Can you say "he has a complete hold over"?) the Jekyll aspect, so that he is left in front of two choices.
5) He may either choose a life of crime and deprivity or the Jekyll aspect must eliminate Hyde by killing him. He eventually opts for the second choice.

1) Dr Jekyll creates a potion capable of realizing his evil side.

2) For this purpose, he uses a particular salt, adds it to other components, and brings them to the boil. Once the boiling has subsided, he drinks the potion.

3) First, he suffers horrible agonies, but then he experiences a sense of freedom in his increased weakness. His evil side has always been dominated by the good and is therefore much less exercised.

4) Once Hyde, his evil side, is released, he has a complete hold over the Jekyll aspect, so that he is left in front of two choices. [<~~I don't know what those last 6 words mean.]

5) He may choose either a life of crime and depravity or the Jekyll aspect must eliminate Hyde by killing him. He eventually opts for the second choice.

Be sure to compare yours and mine VERY CAREFULLY so you catch everything, including spaces, commas, spelling, etc.

And here's the comma-use website again in case you need explanations:
http://grammar.ccc.commnet.edu/grammar/commas.htm

Sure, let's check the sentences and provide suggestions for alternate/clarifying words:

1) Dr Jekyll creates a potion capable of unleashing (or revealing) his evil side.
2) For this purpose, he uses a specific salt, combines it with other components, and brings them to a boil. Once the boiling has ceased (or the mixture has stopped boiling), he drinks the potion.
3) Initially, he endures excruciating agony, but then he experiences a sense of liberation in his heightened vulnerability. His evil side has always been subdued by the good and is therefore much less practiced.
4) Once Hyde, his evil side, is unleashed, he gains control over (or has complete mastery over) the Jekyll aspect, leaving him with two options.
5) He can either embrace a life of crime and debauchery or the Jekyll aspect must eliminate Hyde by killing him. Ultimately, he chooses the latter option.