Formula to Find Normality of a Solution

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Many chemical substances are available in a dissolved liquid form, rather than a solid form. Liquid chemicals are easier to dispense and measure than solid ones, especially since the solid form is usually a powder. However, the stoichiometry of chemical reactions is complicated by the liquid delivery method. Stoichiometry performs calculations using the amount of the desired substance being placed into the equations. The liquid used to dissolve the substance will not participate in the reaction, and stoichiometry will not take that liquid in to account in the reaction. The amount of the reacting substance being delivered can be determined by finding the normality of the solution. Use these tips to learn how to calculate normality.

Steps

1

Gather information about the equivalent weight of the reacting substance. Consult chemical reference books to find out the valence and the molecular weight of the substance. Molecular weight is the ratio of the mass of 1 molecule of the substance to the mass (one carbon12 molecule divided by 12.) Valence is determined by the maximum number of subatomic valence or atom to atom bonds that the substance may form with other substances.^[1] This information will be required to determine normality.
2

Figure the equivalent weight of the substance. The equivalent weight of the substance is equal to the molecular weight divided by the valence.^[2]

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3

Calculate normality. Normality is the concentration of the substance of interest in a dissolving liquid. Therefore, normality is a property of the mixture, and will vary with the use of more or less dissolving liquid to place the substance of interest into a solution.^[3] Normality is the number of grams of the substance of interest divided by (the equivalent weight of the substance times the amount of dissolving liquid).^[4]
4

Try an example. Dissolve sodium chloride (NaCl) in water. Sodium chloride has a valence of 1 and a molecular weight of 58.443. Therefore, the equivalent weight is 58.443/1 or 58.443. 1 gram of NaCl is dissolved into 0.05 L of water, so the normality of the solution is 1/(58.443 x 0.05) or 0.342.

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Question

How do I calculate my normality?

You can use the formula N= weight of substance in grams*1000/ equivalent weight of substance*volume required in mL.
Question

How do I prepare a 2N HCl solution?

Weigh 7.29g of HCl in a 100ml volumetric flask. Add deionized water to 100ml and shake for a 2N HCl solution.
Question

3.65 g of HCl is present in 100mL solution. What is its normality?

It's 1N, 1 molecular weight in grams per 1 liter (1000 mL) solution. Molecular weight of HCl is 1 (H) + 35.5 (Cl) = 36.5.
Question

How can I prepare 0.02N H2SO4?

You prepare a 0.01 molarity solution of sulphuric acid. It itself will be a 0.02N H2SO4 solution because normality=molarity*(no of H+ ions it can provide)---(for an acid). H2SO4 has 2H+ ions, so you will get the desired solution.
Question

How do I prepare 1N Hcl solution for 100 Ml?

Just weigh 3.65 grams of HCl and put in a conical flask and make it up to the 100ml mark using water.
Question

What are the steps to calculate the normality of NaCl?

The equivalent weight of NaCl is the same as the molecular weight which is 40. For example, to prepare a 1N NaCl solution you need to dissolve 40g of NaCl in 1000mL of water. You can also use the formula Normality= weight of substance in Grams* 1000/ equivalent weight*volume required in mL.
Question

How would I prepare 10 N of concentrated H2SO4 (25 ml) whose molecular weight is 98.07?

First, find the equivalent weight. Use this formula: mol. weight / basicity (or n factor), giving you 49.03. Then, find normality using the weight of solute x 1000 / equivalent weight x volume of solution in ml, which would ultimately give you 12.26 grams. Therefore, you have to use 12.26 g of H2SO4 to prepare your 10 N concentrated H2SO4 solution.
Question

How do I add .5 ml of a .5 N solution of HCL when my HCL is .1 N?

You cannot -- your stock solution is 0.1N when you require a solution of 0.5N. You can always decrease the concentration of your stock, but you cannot increase it.
Question

How do I calculate the normality of 10% of NaOH solution?

10% NaOH means 10g of NaOH in 100 ml. Normality=molality.number of protons used molality=mass/RAM x volume(L) =10g/(40x0.1) =2.5M therefore normality=2.5Mx1 =2.5N
Question

When 3.56 g hcl is present in 500ml of solution, what will be its normality?

It should be as follows: H = 1.008, Cl = 35.45, 1 M 36.45, V=1, e.w = 36.45 / 1 =36.45, N = 3.56 G Hal/ 36.45 X 1 = 0.098.