Hey there!
Molar mass NH₃ = 17.031 g/mol
Number of moles = mass of solute / molar mass
Number of moles = 81.25 / 17.031
Number of moles = 4.7707 moles of NH₃
Volume in liters of solution :
1500 mL / 1000 => 1.5 Liters
Therefore :
Molarity = number of moles / Volume in liters
Molarity = 4.7707 / 1.5
Molarity = 3.180 M
Hope this helps!
