Final answer:
The pKa value of ibuprofen is generally around 4.9, indicating its acidic strength in water. This value is essential for understanding the drug's behavior in the body.
Step-by-step explanation:
The pKa value of ibuprofen is a measure of the strength of the acid in water. To determine the pKa value, one would typically refer to a table or literature that lists pKa values for various compounds. It seems the information provided does not directly contain the pKa value of ibuprofen; however, typically, the pKa of ibuprofen is reported to be around 4.9. Therefore, the correct answer would be 2) 4.9. It's worth noting that pKa values are crucial for understanding the pharmacokinetics and pharmacodynamics of drugs, as they influence solubility and absorption.