Molar mass NH4Cl is 14+4(1)+35.45 = 53.45g/mol. 3.50g /53.45g/mol = 0.06548mol NH4Cl in 250mL. Molarity is moles/liter. 250ml*4 = 1 L, so 0.6548 x 4 = 0.2619 M!
Molarity is the concentration of a solution expressed as the number of moles of solute per litre of solution.
To get the molarity, you divide the moles of solute by the litres of solution.
Molarity = moles of solute / litres of solution
To calculate the molarity of a solution, you need to know the number of moles of solute and the total volume of the solution.
Calculate the number of moles of solute present.
Calculate the number of litres of solution present.
Divide the number of moles of solute by the number of litres of solution.