Investigating the Concentrations of Unknown Acids

Investigating the Concentrations of Unknown Acids

Aim

To find out each of the concentrations of the hydrochloric acids in

the Winchesters labelled A-E. This is going to be carries out by

titrating the acid with NaOH.

Equipment needed for this investigation

Pipette - 25ml

Burette

Phenolphthalein

Conical flask

Beaker

Funnel

Pipette filler

Clamp

NaOH - the known acid of 0.1M

HCl - the unknown concentration of acids

White tile

My predictions

I predict that the different acid solutions of the HCl will be less

than 0.1M because the Winchesters were topped up with water, which

would have obviously weakened the concentration of the acid making the

number of moles less than 0.1.

Safety precautions when doing the experiment:

v The equipment should be used carefully to prevent breakage of any

glass.

v The acids should be used carefully avoiding spillages and if any

acid came into contact it should be rinsed with water immediately to

prevent any irritation to the skin.

Planning

All the equipment is gathered together first and made sure that it is

clean and safe to use.

25ml of the unknown concentration of the HCl is measured using a

pipette and taken using a pipette filler, the liquid is then drained

into a clean conical flask. 3 drops of phenolphthalein indicator is

added to 25ml of HCl.

The burette is securely placed onto the clamp and the NaOH is poured

into the burette using a funnel and making sure that the tap at the

bottom is closed. The conical flask containing the HCl and

Phenolphthalein is placed on a white tile at the bottom end of the

burette.

The tap of the burette is opened to slowly release the NaOH while

swirling the conical flask to combine the two acids. The NaOH is

steadily added until the solution in the conical flask turns a pale

pink colour. If the solution stays the pale pink for up to 20 seconds