This method, called a complexometric titration, is used to find the calcium content of milk, the 'hardness' of water and the amount of calciumcarbonate in various solid materials. The method uses a very large molecule called EDTA which forms a complex with calcium ions. ... This solution is then titrated with EDTA.
Lab coats, safety glasses and enclosed footwear must
be worn at all times in the laboratory.
Note that the concentrated (8mol L-1) sodium
hydroxide solution used is highly corrosive and
should be handled with extra care: ideally wear
rubber gloves when preparing and handling it.
This method, called a complexometric titration, is used
to find the calcium content of milk, the ‘hardness’ of
water and the amount of calcium carbonate in various
The method uses a very large molecule called EDTA
which forms a complex with calcium ions. EDTA stands
for acid. A blue dye called
Patton and Reeder’s indicator (PR) is used as the
indicator. This blue dye also forms a complex with the
calcium ions changing colour from blue to pink/red
in the process, but the dye–metal ion complex is less
stable than the EDTA–metal ion complex. As a result,
when the calcium ion–PR complex is titrated with EDTA
the Ca2+ ions react to form a stronger complex with
For the titration, the indicator is added to the sample
solution containing the calcium ions and forms the
pink/red calcium ion-indicator complex (Ca-PR). This
solution is then titrated with EDTA. The endpoint occurs
when the solution turns blue, indicating that the Ca-PR
complex has been completely replaced by the calcium
ion-EDTA complex and the PR indicator reverts to its
The reaction is:
Ca-PR + EDTA4− → PR + [Ca-EDTA]2−
Note: Ca-PR is pink/red and PR is blue.
10 and 20 mL pipettes
250 mL conical flasks
100, 250 and 500 mL volumetric flasks
pH indicator paper
10 mL and 100 mL measuring cylinders
burette and stand
EDTA: acid 0.025 mol L−1
solution. If possible, dry 5 g of the disodium salt of EDTA
for several hours or overnight at 80°C, allow to cool.
Weigh 4.65 g of the dried EDTA salt and dissolve it in
500 mL of distilled water in a volumetric flask.
Patton-Reeder indicator triturate: a small amount
may be available from Outreach at the University of
Canterbury, see contact details on back page.
Sodium hydroxide solution: (8 molL-1). (See safety
notes) Weigh 32 g of solid sodium hydroxide into a 250
mL conical flask and carefully dissolve in 100 mL of
distilled water. The solution will get very warm as the
NaOH dissolves; the temperature may be controlled by
sitting the bottom of the flask in a small basin of cold
Dilute hydrochloric acid solution: (1-2 mol L−1)
Dilute sodium hydroxide solution: (1-2 mol L−1
Mark me as brainliest
HOPE IT WILL HELP YOU
A few drops of an indicator are added to a water sample. Then, a compound called EDTA (short for ethylenediaminetetraacetic acid) is slowly added to the sample. EDTA forms complexes with the calcium and magnesium ions that are red. Because of the presence of the indicator, when all of the metal ions have formed complexes with the EDTA, the solution will change color from red to blue. If you know how much EDTA you have added and the stoichiometry of the chemical reaction, you can calculate how many metal ions were initially present in the water sample.
Dark, leafy greens are incredibly healthy, and some of them are high in calcium. Greens that have good amounts of this mineral include collard greens, spinach and kale
HOPE IT HELPS
MARK THIS AS BRAINLIEST
it is a mineral supplement and medication absorbed as calcium lactate and it only contain 0.93percent calcium ion
it is slowly soluble in water
sorry I don't know PlZ follow me