Detergents (1 Viewer)

[alez]

Perform a first hand investigation to distinuish between anionic, cationic and non-ionic synthetic detergents, in terms of chemical composition and uses

Anyone done an experiment for this?

 

[Undermyskin]

Noops. But at the first glance, do you think we test the conductivity? lolz. Ah, I think we test if they lather much (just shake them vigorously?). This's gonna indicate the non-ionic.

 

[alez]

well i did it today, just measuring lather
quite boring and disappointing actually

 

[Undermyskin]

Hang on a sec. With lathering, how to you compare anionic and cationic. Don't say that you add a same amount of each detergents with same amount of water and same amount of Calcium ions (to make hard water), shake them with similar forces and compare their froth. It's gonna be bloody hard to observe that way. The amount of bubbles should be sort of equal! hix

 

[alez]

just add approx same amts of each detergent to water, shake and then measure amt of lather. anionic lathers a lot more than cationic. i ended up with 8.5cm for anionic compared with about 1cm for cationic

 

[minijumbuk]

Hang on a sec. With lathering, how to you compare anionic and cationic. Don't say that you add a same amount of each detergents with same amount of water and same amount of Calcium ions (to make hard water), shake them with similar forces and compare their froth. It's gonna be bloody hard to observe that way. The amount of bubbles should be sort of equal! hix

I thought detergents don't form scum in hard water though =O

 

[Undermyskin]

You're right, they form soluble complex ions. With anionic detergents, hard water to some extent reduces the effectiveness of them by forming these complex ions. Thus, less amount of detergents truly participate in the washing process. I didn't say they form scum!

But theoretically, I'd expect anionic to give less froth in hardwater. Alez, why didn't you use hardwater? You weren't told which one was cationic/anionic detergent, yeah?

 

[alez]

got 3 samples, just added them to water and shook in test tube, measured height of lather and deduced which one was anionic, cationic and non ionic
just using tap water. not too complicated