Table of Contents
- 1 Why is Murexide indicator used in determination of calcium?
- 2 Why EDTA is used for determination of calcium ions in tap water?
- 3 Why buffer solution is added in sample solution during complexometric titration during determination of hardness?
- 4 Why is murexide a suitable indicator?
- 5 Which indicator is used in hardness determination?
- 6 Which method can be used to detect the end point of an EDTA titration?
- 7 Why ammoniacal buffer is added during the determination of the hardness of water?
- 8 How is the hardness of the water determined?
- 9 How are scale deposits an indicator of hard water?
- 10 What kind of minerals are in hard water?
Why is Murexide indicator used in determination of calcium?
Use. Murexide is used in analytical chemistry as a complexometric indicator for complexometric titrations, most often of calcium ions, but also for Cu, Ni, Co, Th and rare-earth metals. It functions as a tridentate ligand. Its use has been eclipsed by calcium-ion selective electrodes.
Why EDTA is used for determination of calcium ions in tap water?
Calcium and magnesium ions dissolved in water cause water hardness. Ethylenediaminetetraacetic acid (EDTA), shown on the right in its deprotonated form, is commonly used in a titration to determine the concentration of Ca2+ and Mg2+ ions in water because both ions form complexes with EDTA.
What is the purpose of an auxiliary complexing agent?
An auxiliary complexing agent is added to an EDTA titration to prevent hydroxide formation. This is added where one of the solutions of titration is a metal cation. This bond between the agent and the metal is important.
Why buffer solution is added in sample solution during complexometric titration during determination of hardness?
A buffer solution is used in EDTA titration because it resists the change in pH. This is because all the reactions between the metal ions and EDTA are pH-dependent. Stay tuned with BYJU’S to learn more about other concepts such as complexometric titration.
Why is murexide a suitable indicator?
The indicator used is murexide which is a different colour when freq compared to its colour when it is attached to Ni2* ions. Murexide is a suitable indicator since it binds less strongly to the Ni2* ions than does EDTA.
Why is murexide preferred over eriochrome black T in the estimation of nickel using EDTA?
➡️ Murexide is used normally as its blue/purple end point for the tritation is more easily observed. ➡️Also less murexide is needed for titrations, this is a good thing since indicators by and large are weak acids or bases themselves, thus mimising the impact on the titration figures.
Which indicator is used in hardness determination?
Eriochrome Black T
Eriochrome Black T is a complexometric indicator that is used in complexometric titrations, e.g. in the water hardness determination process. It is an azo dye.
Which method can be used to detect the end point of an EDTA titration?
The most common way to detect the end point in EDTA titrations is with a metal ion indicator. Alternatives include a mercury electrode and an ion-selective electrode (Chapter 14, 8th Ed.).
How does EDTA titration work?
EDTA is short for ethylenediaminetetraacetic acid. For the titration, the sample solution containing the calcium and magnesium ions is reacted with an excess of EDTA. The indicator is added and remains blue as all the Ca2+ and Mg2+ ions present are complexed with the EDTA.
Why ammoniacal buffer is added during the determination of the hardness of water?
As far as I know the pH needs to be at least 10 for the EDTA to let go of its H+ ions so we get the EDTA4- solution we need for the reaction with Mg2+ and Ca2+. For this reason we need a buffer which will keep the total solution at pH10 even if we have to add considerable amounts of EDTA.
How is the hardness of the water determined?
Learn a lot more about water hardness on the Water Science School site. The simple definition of water hardness is the amount of dissolved calcium and magnesium in the water. Hard water is high in dissolved minerals, largely calcium and magnesium. You may have felt the effects of hard water, literally, the last time you washed your hands.
How does calcium carbonate react with hard water?
For example, when hard water is heated, Ca2+ions react with bicarbonate (HCO3-) ions to form insoluble calcium carbonate (CaCO3), as shown in Equation 1. (1) This precipitate, known as scale,coats the vessels in which the water is heated, producing the mineral deposits on your cooking dishes.
How are scale deposits an indicator of hard water?
Scale deposits are a typical indicator of hard water. Hard water (or water hardness) is a common quality of water which contains dissolved compounds of calcium and magnesium and, sometimes, other divalent and trivalent metallic elements.
What kind of minerals are in hard water?
Hard water is a common quality of water which contains dissolved compounds of calcium and magnesium and, sometimes, other divalent and trivalent metallic elements.