**OVERVIEW**

A 70% (w/w) Nitric acid can be purchased from several commercial suppliers. It is a clear colorless liquid and can be diluted to prepare solutions of known concentrations. Here we describe a procedure to prepare a 1 M Nitric acid solution using commercially supplied 70% stock solution.

**REQUIREMENTS**

**Reagents and solutions**70% (w/w) Nitric acid solution

Distilled water

**Equipment and disposables**Measuring cylinder/volumetric flask

Beaker (1 Liter)

Magnetic stirrer

**OBJECTIVE**

Preparation of 1 Liter of 1M Nitric acid using concentrated stock solution (70%, w/w)

**PROCEDURE**

**Use personal protective equipment (lab coat, gloves, goggles etc) for your safety and follow the guidelines of your institute.**

**PART I: Calculate how much 70% (w/w) concentrated stock Solution is required to prepare 1 L of 1M Nitric acid solution**

**Step 1: Calculate the molarity of 70% (w/w) concentrated Nitric acid solution**The procedure to calculate molarity of 70% (w/w) concentrated Nitric acid solution is described in detail in the post “Molarity of 70% (w/w) Nitric Acid (HNO3)”. From this post, you will know that the molarity of 70% (w/w) concentrated Nitric acid solution is 15.7 M.

**Step 2: Calculate how much concentrated stock solution is required to prepare 1L of 1M Nitric acid solution using dilution method.**

Dilution method is described in detail in the post “Preparing Working Solution from Stock Solution by Dilution”.

Use the following formula to calculate the volume of concentrated solution required for the preparation of 1 liter of 1M solution of hydrochloric acid solution

Formula: C_{f} x V_{f} = C_{S} x V_{S}

C_{f} (concentration of diluted (final) solution) = 1M

V_{f} (volume of diluted (final) solution) = 1 liter

C_{S} (concentration of stock solution) = 15.7 M

V_{S} (volume of stock solution) = ? (unknown)

Place all values in the formula:

1 x 1 = 15.7 x V_{S}

V_{S} = 1 x 1/ 15.7 = 0.0637 liter (63.7 ml)

So you need 0.0637 liters of 70% (w/w) concentrated Nitric acid solution to prepare a 1 liter of 1M Nitric acid solution.

**Step 3: Calculate the volume of solvent to be taken.**

Final volume of diluted solution = 1Liter

Volume of concentrated solution = 0.0637 Liter

Volume of solvent (water) required = 1 – 0.0637 = 0.9363 Liter

So you need to mix 0.0637 liter (63.7 ml) of concentrated solution to 0.9363 liter (936.3 ml) water to prepare 1 liter of 1 M Nitric acid solution.

**PART II: Solution preparation**

**Step 4: Transfer 936.3 ml water in a beaker/volumetric flask/measuring cylinder. Add 63.7 ml of 70% Nitric acid stock solution and mix it to prepare a homogeneous solution.**Note: In case you have not calculated the amount of water to be added, just take ≈ 500 ml water in a volumetric flask/measuring cylinder (capacity 1L) and add 63.7 ml of 70% Nitric acid stock solution. Now adjust the final volume to 1 liter with water. Mix it.

**STORAGE **Solution can be stored at room temperature.