TO COMPARE CLEANSING ACTION OF DETERGENT 'B' AND DETERGENT 'A' WITH THE HELP OF STALAGMOMETER

APPARATUS REQUIRED

• Weighing balance

• 100ml beaker.

• stalagmometer

• Pyknometer(specific gravity bottle)

CHEMICALS REQUIRED

• Detergent 'A' Solution 

• Detergent 'B' Solution 

• distilled water

PRINCIPLE

The surface tension of each of detergent solution of same mass percentage is determined number method using the formula, rx÷rw= nw×ds÷nx×dw

where,

rs and rw are surface tension of detergend and water respectively

ns nw are number of drops made by stalagmometer for some volume of detergent solution and water, dw are their densities.

If Ms and Mw are weights of same volume of the solution and water then.

ds÷dw = Ms/v ÷ Mw/v = Ms ÷ Mw

i.e. the ratio of densities is ratio of their weight in given pyknometer.

Soap and detergent form associative collids of micelles in aqueous solutions which decreases the surface tension of water. As the surface tension decrease the extent of adsorption of dirt in micelles increases and the cleaning of the detergent would be Thigh.

PROCEDURE

• we washed the given apparatus with distilled water and checked that there should not be any obstruction in the capillary tube of the stalagmometer.

• The empty dry and clean pyknometer (specific gravity bottle) was weighed. It is then filled with the given detergent solution and distilled water in turn. The outer wall of apparatus was wiped with dry filter paper in each turn and weighed.

• Stalagmometer was clamped vertically in stand

• 0.1% Sol" of of given detergent solution was prepared in 100ml volumetric flask. Took 1g of detergent in flask, made volume 100ml with water and then was shaked carefully to make it homogeneous)

• The given detergent solution (wheel, surf excel) was taken in a clean beaker and was sucked up in a and stolagmometer by fixing rubber tube untill solution crossed upper marking.

• The pinch cook of rubber tube was adjusted number of complete drops were counted as solution was passing from upper mark until it just crossed lower mark of stolagmometer.

• The process was repeated 3 times each similar process was carried out for another detergent solution and distilled water also

OBSERVATION:

Tempr t°C = 32°C (rw)

surface tension of water at t°c = 71.34 dyne/cm.

For density:

wt. of dry and clean pyknometer (W₁) =18.198g.

wt. of Pyknometer+distilled water (W2) = 48.61g.

wt. of pyknometer + soln 'X' (W3) = 44.73 g.

wt. of pyknometer + Soln 'Y' (W4) : 44.58 g. 

Solution	No. Of Drops	Mean(No.of Drops)
Distilled (Water)	40 41 39	40 (nw)
Detergent ‘A’ “Wheel”	98 100 99	99(ny)
Detergent ‘B’ “Surf Excel”	115 115 117	116(nY)

 

CALCULATION

wt. of water = w₂-w₁ = (48.61-18·19) g.
                               dw = 30.42g.
wt. of Soln 'X' = W3-W1 = (44.73-18·19) g.
                                      dx = 26.54g.
wt. of soln 'Y' - W4-W1 = (44-58-18·19)g.
                                     dr = 26.398 g.

For detergend 'X' (wheel)

rx÷rw= nw×ds÷ns×dw
rx = {nw×ds÷ns×dw} × rw
rx = {40×26.54÷99×30.42}×71.34
rx = 25.14 dyne/cm

For detergent 'Y' ( surf excel)

ry÷rw = nw×dy÷ny×dw

{40x26.89÷116×30.42}× 71.34

ry = 21.34 dyne/cm

RESULT

Hence, the surface tension of surf excel solution was less than the surface tension of wheel solution 

Therefore surf excel acts as a better cleansing reagent.

CONCLUSION

Therefore, cleansing action of detergent

solution can be determined by comparing their surface tension.

TO DETERMNNE CMC (CRITICAL MICELLE CON CONT- RATION) OF GIVEN SOAP BY SURFACE TENSION METHOD USING STALAGMOMETER