CBSE Class 12-science Answered

Identification test for Monosodium Glutamate:

Test: Dissolve 250 mg of sample (accurately weighed), in 100 ml of glacial acetic acid. Add few drops of water which will enhance the dissolution. Titrate it with 0.1 N perchloric acid in glacial acetic acid and determine the end point potentiometrically. Run a blank determination in the same manner and correct for the blank.

Each ml of 0.1 N perchloric acid is equivalent to 9.356 mg of C₅H₈NNaO₄.H₂O

Identification test for Disodium Guanylate:

Test: Dissolve 500 mg of sample (accurately weighed) in 1000 ml volumetric flask in 0.01 N HCl and dilute to volume with 0.01 N HCl. Mix it properly. Transfer 10 ml of this solution to 250 ml volumetric flask and dilute to volume with 0.01 N HCl. Test this solution on spectrophotometer. It shows maximum absorbance at 256 2 nm. (Use Disodium Guanylate as reference standard)

Identification test for Disodium Inosinate:

Test: Dissolve 500 mg of sample (accurately weighed) in 1000 ml volumetric flask in 0.01 N HCl and dilute to volume with 0.01 N HCl. Mix it properly. Transfer 10 ml of this solution to 250 ml volumetric flask and dilute to volume with 0.01 N HCl. Test this solution on spectrophotometer. It shows maximum absorbance at 250 2 nm. (Use Disodium Inosinate as reference standard)

Presence of wax:

Please mention the type of wax as there are different types of wax used in the food materials. Please mention the type of wax as different analysis test are there for different types of wax.

Presence of excess lead:

If you add concentrated hydrochloric acid to excess, the lead(II) chloride precipitate will dissolve again. Complex ions like PbCl₄ ^2- are produced, and these are soluble in water.

Presence of excess sodium chloride:  

It is done by following methods:

Mohr titration method

Volhard titration method

Dichromat analyser

Quntab strip test

Leaching of dioxins & plasticisers from maggi plastic cups on adding hot water:

Please provide more details.