1st Encounter: When Scorpion is charging you, rotate around him pressing to dodge his attacks. His tail will get stuck in the ground, which is your chance to use strong attacks on him. When he latches on to parts of the environment above you, throw the acid eggs at him that he creates then run up to him and press near him. These are really the only moves you have to worry about this easy fight.
Final Encounter: You will want to stay in the pit until there's acid down there. Dodge Scorpion when he attacks and then use strong attacks while he sits there. After a little bit there will be acid on the ground. Zip Web to the area above the pit. Use the acid eggs he creates against him. You will continue to do this, the fight will move between high and low and he will change his attack pattern a little bit, but you should still be using the same dodge/strong attack tactics. Once you've successfully thrown the eggs 3 times at him, it will end the battle.