Table of Contents
Is murexide an acid base indicator?
It is a purple solid that is soluble in water. The compound was once used as an indicator reagent. Aqueous solutions are yellow at low pH, reddish-purple in weakly acidic solutions, and blue-purple in alkaline solutions….Murexide.
| Names | |
|---|---|
| ChemSpider | 17264 |
| ECHA InfoCard | 100.019.334 |
| EC Number | 221-266-6 |
| PubChem CID | 18275 |
How does murexide work as an indicator?
Murexide (ammonium purpurate) was found to function as an indicator for the complexometric determination of Th. Ammonium purpurate forms a yellow complex with Th that turns pink when an excess drop of EDTA is added to it.
Why murexide is used in determination of nickel?
It is because murexide will not bind strongly with the nickel ions than the binding of EDTA. Hence the metal-indicator bond can be broken easily to form metal-EDTA bond. So murexide is preferred and it has different colour when it is free and when it is binded with nickel ions. Hence it can be indicated easily.
What is the basis of Murexide test?
The murexide test is an analytical technique to identify the presence of caffeine and other purine derivatives in a sample. These compounds do not respond to the common alkaloid detecting tests such as Dragendorff’s reagent.
What is the cause of the purple color of the positive Murexide test?
The murexide test for uric acid consists in the reaction of uric acid with dilute nitric acid, followed by ammonia addition: a purple colouration is produced due to the formation of ammonium purpurate or murexide.
Which indicator is used in estimation of nickel?
A simple, rapid and reasonable selective Complexometric technique for nickel (II) determination using some selected hydroxytriazene as a metallochromic indicator is reported in the present study. The colour change at the end point was from greenish-yellow/yellow to colourless with sharp end point.
Why Murexide indicator is used in the estimation of NI?
But in in the estimation of nickel using EDTA murexide is used as indicator. It is because murexide will not bind strongly with the nickel ions than the binding of EDTA. Hence the metal-indicator bond can be broken easily to form metal-EDTA bond.
Why EDTA is used in for determining nickel?
Determination of nickel using EDTA titrant is carried in alkaline environment. It is better if the environment is slightly alkaline at the beginning of reaction, and becomes more alkaline (from ammonia added). Indicator is murexide, changing color from yellow to violet.
What is the pH of murexide in water?
Murexide in its dry state has the appearance of a reddish purple powder, slightly soluble in water. In solution, its color ranges from yellow in strong acidic pH through reddish-purple in weakly acidic solutions to blue-purple in alkaline solutions. The pH for titration of calcium is 11.3.
What is the name of the compound murexide?
Murexide (NH 4 C 8 H 4 N 5 O 6, or C 8 H 5 N 5 O 6 ·NH 3), also called ammonium purpurate or MX, is the ammonium salt of purpuric acid. It is a purple solid that is soluble in water. The compound was once used as an indicator reagent.
What is the color of murexide in acid?
Murexide. Murexide in its dry state has the appearance of a reddish purple powder, slightly soluble in water. In solution, its color ranges from yellow in strong acidic pH through reddish-purple in weakly acidic solutions to blue-purple in alkaline solutions. The pH for titration of calcium is 11.3.
What is the maximum absorbance of murexide?
Murexide is also used as a colorimetric reagent for measurement of calcium and rare-earth metals; for calcium, the pH required is 11.3, detection range lies between 0.2 and 1.2 ppm, and the maximum absorbance wavelength is 506 nm. [citation needed]