when we make CH3MgX first we take Mg in baloon.then we active it with I2 and finally we increase CH3Cl. we know product is very sensitive in air then we carry a mount of it with syring. Now how can we calculate molarity of product becouse we donot know yield. thanks

To calculate the molarity of the product when you don't know the yield, you can use the concept of the limiting reagent.

1. Determine the limiting reagent: Start by identifying the limiting reagent in the reaction. The limiting reagent is the reactant that is completely consumed and determines the amount of product that can be formed. In this case, you can identify the limiting reagent by comparing the number of moles of each reactant used.

2. Calculate the moles of limiting reagent: Once you have identified the limiting reagent, calculate the number of moles of the limiting reagent used in the reaction. This can be done by dividing the mass or volume of the limiting reagent by its molar mass or molar volume.

3. Use stoichiometry to calculate moles of product: Next, use the balanced equation for the reaction to determine the mole ratio between the limiting reagent and the product. This can be found by looking at the coefficients in the balanced equation. Multiply the moles of the limiting reagent by the mole ratio to calculate the moles of product formed.

4. Calculate molarity: Finally, calculate the molarity of the product by dividing the moles of product by the amount of solvent used to prepare the solution. The amount of solvent can be determined by measuring the volume of the solution.

Since you mentioned carrying a certain amount of the product in a syringe, you can measure the volume of the solution in the syringe and use that to calculate the molarity.

Keep in mind that this calculation assumes 100% yield, meaning that all reactants are fully converted to the product. In reality, the actual yield may be less than 100%, so the calculated molarity will be an upper limit estimation.