To determine the concentration of a limewater solution

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To determine the concentration of a limewater solution

Aim

In this experiment I will be determining the concentration of limewater solution, in g dm-3, by titrating the calcium hydroxide solution, Ca (OH)2, with dilute hydrochloric acid, HCl.

Introduction

One of the most accurate ways of determining the concentration of a given solution is to establish how much of another solution will neutralize it. This type of experiment is called a titration. The solution in question is limewater , which is an alkali, so in order to neutralize it, we require an acid. A good acid for this experiment would be hydrochloric acid. This is because the products given off when mixed with the limewater are not harmful, and hydrochloric acid is a strong acid, so the end-point (the point where the solution has been neutralized,) will be more profound.

The equation I have looked briefly upon above is shown below. This is the balanced equation for titrating the limewater solution with hydrochloric acid is as follows:

The hydrochloric acid available is far too concentrated to be used safely and accurately in this experiment. Therefore I will need to make a standard solution of it. "A standard solution is one which is made up to have a known concentration of a known solute."

Equipments

The things that I will need are as follows:

* A volumetric flask that has 250 cm3 clearly marked

* Methyl orange indicator

* A stand to hold the burette rigidly

* I will need distilled water, which will be needed for dilution

* Four 250 cm3 conical flasks

* 250 cm3 of limewater which has been made such that it contains approximately 1g dm-3 of calcium hydroxide

* Approximately 250 cm3 of 2M hydrochloric acid

* A pipette to pipette out 25 cm3 of Ca(OH)2

* A burette, which I'll need for the titration of Ca(OH)2 with HCl

* Two 10 cm3 measuring cylinder will be used for the dilution. This will be needed to measure out the HCl.

* A funnel which will aid me in putting the HCl into the burette and I will also need a white tile, which will help me to clearly see the reaction taking place
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Dilution

As I've stated above, I'll be provided with 2M hydrochloric acid. This is far too concentrated, so I will have to dilute this concentrated acid to approximately 0.1 moles dm-3.

In order to dilute the HCl to 1 molar; I will need to apply the formula shown below:

C1V1=C2V2

We are given the concentration of the HCl, which is 2.00mol dm-3, this is C1.

We are also given the volume of distilled water, which is 250cm3, this is V2.

We want to make the concentration of HCl into 0.1 ...

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