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QJEEM16Ch605e: JEE Main 2016 Chemistry - Class 12 JEEM16Ch605e Solution: Gold numbers of some colloids are : Gelatin : 0.005 - 0.01, Gum …
Gold numbers of some colloids are : Gelatin : 0.005 - 0.01, Gum Arabic : 0.15 - 0.25; Oleate : 0.04 - 1.0; Starch : 15 - 25. Which among these is a better protective colloid ?
Multiple Choice Options
- A Gelatin
- B Gum Arabic
- C Oleate
- D Starch
Step-by-Step Verified Solution
Gold number of a protective colloid is a minimum weight of it in milligrams which must be added to 10 ml of a standard red gold sol. so that no coagulation of the gold sol. (i.e. change of colour from red to blue) takes place when 1 ml of 10% sodium chloride solution is rapidly added to it. Obviously, smaller the gold number of a protective colloid, the greater is the protective actioin.
It is given that the gelatin has lowest gold number thus, it would serve as a better protective colloid than colloids in the rest of the options.