1 gram of HNO3 will be equal to 1/63.01 moles. Therefore, we can say that 1 liter of Nitric acid contains 15.6976 moles or in other words molarity of 70% (w/w) Nitric acid is equal to 15.6976 M.
Known values
Molecular weight of HNO3 63.01 g/mole
Concentration of Nitric acid 70% (% by mass, wt/wt)