# Molarity of 70% (w/w) Nitric Acid (HNO3)

• Nitric acid is a clear colorless liquid. A 70% (w/w) concentrated Nitric acid can be obtained from different suppliers.
• 70% (w/w) Nitric acid means that 100 g of Nitric acid contains 70 g of HNO3.
• The density of 70% (w/w)Nitric acid is 1.413 g/ml at 25°C which means that the weight of the 1 ml of Nitric acid is 1.413 gram at 25°C.
• Molarity refers to the number of moles of the solute present in 1 liter of solution.
• In simple words, 1 mole is equal to the atomic weight of the substance. For example, 1 mole of HNO3 is equal to 63.01 grams of HNO3 (molecular weight = 63.01).

## Calculation procedure:

Step 1: Calculate the volume of 100 grams of Nitric acid.
Formula:
Density =  weight / volume or
Volume =  weight / density or
Volume of 100 gram of Nitric acid: 100/1.413 =  70.771 ml

Note: 70% (w/w) Nitric acid means that 100 g of Nitric acid contain 70 g of HNO3.

The volume of 100 grams of Nitric acid is 70.771 ml. That means 70 grams of HNO3 is present in 70.771 ml of Nitric acid.

Step 2: Calculate how many grams of HNO3 is present in 1000 ml of Nitric acid.
70.771 ml of Nitric acid contain    = 70 grams of HNO3
1 ml of Nitric acid will contain       = 70/70.771 grams of HNO3
1000 ml of Nitric acid will contain = 1000 x 70/70.771 = 989.106 grams of HNO3
1000 ml of Nitric acid will contain 989.106 grams of HNO3

Step 3: Calculate the number of moles of HNO3 present in 989,106 grams of HNO3.
63.01 grams of HNO3 is equal to 1 mole.
1 gram of HNO3 will be equal to 1/63.01 moles.
989.106 grams will be equal to = 989.106 x 1/63.01 = 15.6976 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.

Use Calculator to calculate the molarity of concentrated Nitric acid (HNO3) when concentration is given in % by mass (w/w)
Nitric acid (HNO3) Molecular weight: 63.01 g/mol

Concentration of Nitric acid in % (wt/wt) : % (wt/wt)

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Density of glacial Nitric acid: g/ml

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Molarity of Nitric acid: 15.698 M 