Soaps are metal salts of long chain fatty acids prepared from oils and fats, while detergents are sodium salts of long chain hydrocarbons made from petroleum. Soaps cannot be used in hard water as they form insoluble precipitates, but detergents do not form precipitates and can be used in soft, hard, or salt water. The document discusses the production, structures, cleansing actions and advantages/disadvantages of soaps and detergents.

2.  SOAP
• Introduction
• Saponification
• Soap molecule(Micelles)
• Cleansing action of soaps
• Advantagesand
disadvantages
 DETERGENT
• Introduction
• Classification of
detergents
• Cleansing action of
detergents
• Advantagesand
disadvantagesof
detergents
 DIFFERENCES
BETWEEN SOAPSAND
DETERGENTS

3.  Soapsarethesodium and potassium saltsof
thelong chain carboxylic acid. A soap
moleculeconsistsof along hydrocarbon
chain (composed of carbonsand hydrogen's)
with acarboxylic acid on oneend which is
ionic bonded to metal ion usually asodium or
potassium.

4.  A soap hasalargenon-ionic hydrocarbon group and an
ionic group COO-Na+.
 It isasalt of astrong base(NaOH) and aweak acid
(carboxylic acid), so asolution of soap in water isbasic
in nature.

5.  Sodiumstearic (Chemical formula:
C17H35COO-Na+)
 Sodium stearic soap isthesodium salt of along chain
saturated fatty acid called stearic acid. Sodium stearic
soap hasalong alkyl group (C17H35) and an ionic
carboxylategroup (COO-
Na+
).

6.  Sodiumpalmitate (Chemical formula:
C15H31COO-Na+)
 Sodium Palmitate‘soap’ isthesodium salt of long
chain saturated fatty acid called stearic acid
(C15H31COOH).

7. A soap moleculeismadeup of two parts: along
hydrocarbon part and ashort ionic part containing COO-
Na+
group. Thesoap moleculeissaid to haveatadpole
structure.

8.  A soap moleculehastwo ends
with different properties-
1. A long hydrocarbon part which
ishydrophobic (i.e. it dissolves
in hydrocarbon).
2. A short ionic part containing
COO-Na+ which ishydrophilic
(i.e. it dissolvesin water).
micelle

10.  Theprocessof making soap by the
hydrolysisof fatsand oilswith alkaliesis
called saponification.
 Soap ismadeby heating animal fatsor
vegetableoil with concentrated sodium
hydroxide(NAOH).
 Fat or Oil + NaOH → Soap + Glycerol

11.  When a dirty cloth is put is put in
water containing soap than the
hydrocarbon ends of the soap
molecule in the micelle attach to
the oil or grease particles present
on the surface of dirty cloth. In this
way the soap micelles entraps the
oily particles by using the
hydrocarbon ends. The ionic ends
of the soap molecules remain
attached to the water when the
dirty cloth is agitated in soap
solution. The oily particles presents
on its surface gets dispersed in the
water due to which the cloth gets
clean.

12. Weusesoapson daily basis.
Following aresomeuses
of soaps:-
Washing hands
Washing clothes
Cleaning utensils

13.  ADVANTAGES
 Soaps are
eco-friendly
and bio
degradable
 DISADVANTAGES
 Soaps are not
suitable in the
hard water.
 They have weak
cleansing
properties than
detergents.

14. LIMITATIONS OF SOAPS :-
Hard water contains calcium and magnesium salts. Soap is not
suitable for washing clothes with hard water because of two
reasons :-
When soap is used for washing clothes with hard water, a large
amount of soap is wasted in reacting with the calcium and
magnesium ions of hard water to form an insoluble precipitate
called scum, before it can be used for the real purpose of
washing .
So a larger amount of soap is needed for washing clothes when
the water is hard.
The scum (or the curdy precipitate) formed by the action of
hard water on soap, sticks to the clothes being washed and
interferes with the cleaning ability of the additional soap. This
makes the cleaning of clothes difficult.

15.  Detergents are defined as ammonium,
sulphonate or sulphate salts of long
chain hydrocarbon containing 12-18
carbon atoms.
 Detergents are soap less soaps because
they have all the properties of soaps but
actually they do not contain any soap.
 More common detergents are the
sodium salt of long chain sulphonic
acid.

16.  Detergentsareprimarily surfactants, which
could beproduced easily from petrochemicals.
 Surfactantslower thesurfacetension of water,
essentially making it 'wetter' so that it isless
likely to stick to itself and morelikely to interact
with oil and grease.
 Theionic group in adetergent isSO3¯Na⁺
 They can beused in hard water asthey do not
form curdy whiteprecipitates(scum) with hard
water.

18.  These are so called because a large
part of their molecule are anions and it
is the anionic part of the molecule
which is involved in cleansing action.
 Anionic detergents are of two types:
1. Sodium alkyl sulphate
2. Sodium alkyl benzene sulphonate
 These are used in toothpaste.

19.  They are obtained from long straight
chain alcohols containing 12-18 carbon
atoms.
 Example: Sodium lauryl sulphate and
sodium stearyl sulphate

20.  They are 100% biodegradable
 These detergents are also effective in
slightly acidic medium since they form
alkyl hydrogen sulphated which are
soluble material whereas soaps react
with acidic solution to form insoluble
fatty acid.

21.  These detergents are sodium salt of long
chain alkyl benzene sulphonic acids.
 Most widely used domestic detergent is
sodium 4-(1-dodecyl) benzene
sulphonate (SDS).

22.  These are so named because the major
part of their molecule is cation and it is
the cationic part which is involved in
cleansing.
 They are also called as invert soaps.
 These are quaternary ammonium salts
(bromide, chloride, acetate) containing
one or more long chain alkyl group.

23.  They are more expensive than anionic
detergents.
 They possess germicidal properties thus
used in hospitals.
 Example: cetyl trimethyl ammonium
bromide
 They are used in hair shampoos and hair
conditioner.

24.  They do not contain any ions.
 They are esters of high molecular mass
alcohol obtained by reaction between
polyethylene glycol and stearic acid.
 Example: Polyethylene glycol stearate
 Liquid dishwashing detergents are of non
ionic type.

25.  Synthetic detergentshavethesametypeof molecular
structureassoaps i.e., onelargenon-polar hydrocarbon
group that iswater repelling (hydrophobic) and oneshort
ionic group usually containing the group that iswater
attracting (hydrophilic).
 Thusthecleansing action isexactly similar to that of
soapswhereby theformation of micelles.
 However, synthetic detergentscan lather well even in hard
water. Thisisbecausethey aresolublesodium or
potassium saltsof sulphonic acid or alkyl hydrogen
sulphate.
 Detergentsform solublecalcium or magnesium saltson
reacting with thecalcium ionsor magnesium ionspresent
in water. Thisisamajor advantageof thecleansing
property of detergentsover soap.

26. • Detergentscan beused even with hard water whereas
soapsarenot suitablefor usewith hard water.
• Detergentshaveastronger cleansing action than soaps.
• Detergentsaremoresolublein water than soaps.
• Detergentscan beused in acidic medium whilesoaps
get precipitated in acidic medium.

27.  Many detergentsareresistant to theaction of
biological agentsand thusarenot biodegradable.
Their elimination from municipal wastewatersby
theusual treatmentsisaproblem.
 They haveatendency to producestablefoamsin
riversthat extend over several hundred metersof the
river water. Thisisdueto theeffectsof surfactants
used in their preparation. Thusthey poseadanger to
aquatic life.
 Detergentsconsist of sidechainswhich stop bacteria
from attacking and breaking thechain . Thisresults
in slow degradation of detergent moleculeleading to
their accumulation.

28.  SOAPS
They aremetal saltsof
long chain higher fatty
acids.
Theseareprepared from
vegetableoilsand
animal fats.
They cannot beused
effectively in hard water
asthey producescum
i.e., insoluble
precipitatesof Ca2+,
Mg2+, Fe2+ etc.
 DETERGENTS
Thesearesodium saltsof
long chain hydrocarbonslike
alkyl sulphatesor alkyl
benzenesulphonates.
They areprepared from
hydrocarbonsof petroleum or
coal.
Thesedo not produce
insolubleprecipitatesin hard
water. They areeffectivein
soft, hard or salt water.