Molarity of 48% (w/w) Hydrofluoric Acid (HF)

OVERVIEW

  • A 48% (w/w) Hydrofluoric acid (HF) is a clear colorless aqueous solution of Hydrogen fluoride (HF) gas. It can be purchased from many commercial suppliers.
  • % refers to solution concentration in percentage and “(w/w)” refers to solute and solution amount given in grams (i.e., percentage by weight). This means a 48% (w/w) Hydrofluoric acid contains 48 g of Hydrogen fluoride (HF) per 100 g of solution.
  • The density of 48% hydrofluoric acid is 1.15 g/ml at 25° C. This means the weight of the 1 ml of hydrofluoric acid is 1.15 g at 25°C.
  • Molarity refers to the number of moles of the solute per litre of solution. To calculate the Molarity of 48% (w/w) Hydrofluoric Acid, you need to know how many moles of HF are present in 1 liter of solution.
  • In simple words, 1 mole is equal to the molecular weight of the substance. For example, 1 mole of Hydrogen fluoride is equal to 20.01 g of Hydrogen fluoride (Molecular Weight: 20.01).
  • To calculate the molarity, one must first calculate how much Hydrogen fluoride is present in 1 L of 48% Hydrofluoric acid. Once we know the amount of HF present in 1 L solution, we can calculate the molarity of the solution by dividing the HF amount by the molecular weight.
  • Calculator: Converting Percentage by Mass to Molarity

48% hydrofluoric acid to moles per liter

Calculation procedure

Known values
Molar mass of Hydrogen fluoride20.01 g/mole
Concentration of Hydrofluoric acid 48% (% by mass, w/w)
Density of 37% Hydrofluoric acid
1.15 g/ml

Step 1: Calculate the volume of 100 grams of Hydrofluoric acid.
Formula:

Density = WeightVolume

OR

Volume = WeightDensity

The volume of 100 g of Hydrofluoric acid : 1001.15 = 86.9565 ml

Note: 48% (w/w) Hydrofluoric acid means that 100 g of Hydrofluoric acid contains 48 g of HF.

The volume of 100 g of Hydrofluoric acid is 86.9565 ml which means 48 g of HF is present in 86.9565 ml of Hydrofluoric acid.

Step 2: Calculate how many grams of HF is present in 1000 ml of Hydrofluoric acid.

86.9565 ml of Hydrofluoric acid contains   = 48 grams of HF
1 ml of Hydrofluoric acid will contain      =   4886.9565 grams of HF

1000 ml of Hydrofluoric acid will contain = 1000 x 4886.9565  = 552 grams of HF

1000 ml of Hydrofluoric acid will contain 552 grams of HF.

Step 3: Calculate the number of moles of HF in 552 grams of HF.

20.01 g of HF is equal to 1 mole.

1 g of HF will be equal to 120.01 moles.

552 grams of Hydrogen fluoride will be equal to = 552 x 120.01 = 27.46 moles

Therefore, we can say that 1 liter of Hydrofluoric acid contains 27.46 moles of HF or in other words molarity of 48% (w/w) Hydrofluoric acid is equal to 27.46 M.

Flow diagram: Calculation - Molarity of 48 Hydrofluoric Acid (HF)

Calculator – Calculate the molarity of concentrated Hydrofluoric acid (HF)

Use Calculator to calculate the molarity of concentrated Hydrofluoric acid (HF) when concentration is given in % by mass (w/w)

Hydrogen Fluoride (HF) Molecular weight: 20.01 g/mole

Concentration of Hydrofluoric acid: % (w/w)
(Change the % (w/w) concentration)

Density of Hydrofluoric acid: g/ml
 (Change the density)

Molarity of Hydrofluoric acid: 27.586 M

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