Here's how to calculate the grams of lidocaine in a 150 ml, 2.5 M solution:

1. Calculate the moles of lidocaine:

* Molarity (M) = moles of solute / liters of solution

* We have a 2.5 M solution, and 150 ml is equal to 0.15 L (1000 ml = 1 L)

* Rearranging the formula: moles of solute = Molarity * liters of solution

* moles of lidocaine = 2.5 M * 0.15 L = 0.375 moles

2. Calculate the grams of lidocaine:

* Moles = grams / molar mass

* The molar mass of lidocaine (C14H22N2O) is approximately 234.34 g/mol.

* Rearranging the formula: grams = moles * molar mass

* grams of lidocaine = 0.375 moles * 234.34 g/mol = 87.93 g

Therefore, there are approximately 87.93 grams of lidocaine in a 150 ml, 2.5 M solution.

Important Note: This calculation is for informational purposes only. It is crucial to consult with a qualified chemist or pharmacist for accurate and safe handling and use of any chemical substances, especially medications like lidocaine.