acidsbasesandsaltsppt-converted-220918134444-a932f293.pdf

10th acids bases and salts

1. Acids,basesand
salts

2. ACIDS
The word acid means ‘sour’ and all acids possess these
properties. They are:-
•Soluble inwater
•Corrosive
•Sour in taste
•Produce H+ (hydrogenions)
•Conductelectricity
•pH less than7
•Turns blue litmusred

3. EXAMPLES OF ACIDS
Vinegar (Acetic acid)
LemonJuice (Citric acid)
SoftDrink (Carbonic acid)
BatteryAcid (Sulphuric acid)
StomachAcid (Hydrochloric acid)
AppleJuice (Malic acid)
BlackTea (Tannic acid)

4. BASES
•pH greater than7.
•Usually forms OH
-
ions insolution.
•Neutralizeacids.
•Corrosive
•Bitter intaste.
•They have a soapyfeel.
•Water soluble bases are calledalkali.
•All alkalis are bases but all bases are notalkalis.
•Turns red litmus blue, phenolphthalein to pinkand
methyl orange toyellow.

5. EXAMPLES OF BASES
Ammonia,NH3 (fertilizer, cleaning agent)
Sodium hydroxide, NaOH (cleaning agent, paper, pH regulator)
Sodium carbonate,Na2CO3 (paper, glass, detergent, toothpaste)
Sodium bicarbonate,NaHCO3 (baking soda, fire extinguisher, toothpaste)
Calcium hydroxide, or slaked lime,Ca(OH)2 (whitewashing, paper)
Calcium carbonate,CaCO3(limestone building, blackboard chalk)
Calcium hypochlorite,Ca(ClO)2 (sanitizer, disinfectant)
Potassium hydroxide, KOH (alkaline batteries)
Aluminium oxide,Al2O3 (plastic, glass, paint)
Hydrated iron (III) oxides,Fe2O3.xH2O(rust)

6. TESTING ACID AND BASE WITH
LITMUS PAPER

7. Substances that indicate about the nature of the
given substance are known asindicators.
Types-1.Naturalindicators
2.Syntheticindicators
Natural indicators are obtained from natural
resources like plants eg. Litmus, turmeric, petal
extracts of China Rose, Hydrangea, Red cabbage,
Geraniumetc.
Synthetic indicators are chemically prepared.E.g.
Phenolphthalein, methyl orange, methylred
INDICATORS

8. RED CABBAGE INDICATOR

9. TURMERIC INDICATOR

10. METHYL ORANGE INDICATOR

11. PHENOLPHTHALEIN
ACID BASE

12. OLFACTORY INDICATORS
Indicators that change their smell on coming in contact with an
acid or abase.

13. TRY THIS OUT !

14. Acids + Metals Metal salt + Hydrogengas
2HCl + Zn ZnCl
2
+H
2
H
2
SO
4
+ Zn ZnSO
4
+H
2
Hydrogen gas can be tested by bringing a lighted
splinter close to the mouth of the test tube,
hydrogen gas will burn with a popsound.
REACTION OF ACIDS WITHMETALS

15. REACTION OF
ACIDS WITH
METALS
Reaction of zinc
granules with
dilute sulphuric
acid and testing
hydrogen gas by
burning

16. Base + Metal Metal salt + Hydrogengas
Zn(s)+ NaOH(aq)Na
2
ZnO
2
(aq) +H
2
(g)
sodium hydrogen gas
zincate
REACTION OF BASES WITHMETALS

17. Metal carbonate+ acidMetalsalt+carbondioxide +water
Na
2CO
3 (s)+2 HCl(aq)2NaCl(aq)+H
2O(l)+CO
2(g)
NaHCO
3(s)+HCl(aq)NaCl(aq) +H
2O(l)+CO
2(g)
Brisk effervescence is observed due to the evolution of carbon-di-oxide
Test forCO
2
Lime water turns milky on passing CO
2 through it. Milkiness is due to the
formation of insoluble calciumcarbonate.
Ca(OH)
2 + CO
2 CaCO
3+H
2O
When excess of CO
2 is passed, milkiness will disappear
CaCO
3 + CO
2 +H
2O Ca(HCO
3)
2 ( Calcium Bicarbonate)
REACTION OF ACIDS WITH METAL
CARBONATES & BICARBONATES

18. Acids and bases react with each other to form
salt and water. These reactions are called
neutralizationreaction.
HCl(aq)+NaOH(aq)NaCl(aq)+H
2
O(l)
H
2
SO
4
(aq) + KOH(aq)K
2
SO
4
(aq) +H
2
O(l)
REACTION BETWEEN ACIDS &BASES

19. Metal oxide + AcidMetal salt +water
Metal oxides are usually basic in nature, so this
reaction is also a neutralizationreaction.
CuO(s)+ 2HCl(aq)CuCl
2
(aq) +H
2
O(l)
Black colour changes to bluishgreen
REACTION BETWEEN METAL
OXIDES & ACIDS

20. Nonmetal oxide + Base salt +water
Nonmetal oxides are usually acidic in nature, so it
is also a neutralizationreaction.
CO
2(g)+Ca(OH)
2
(aq)CaCO
3(s)+H
2
O(l)
REACTION OF A NON-METALLIC
OXIDE WITH BASES

21. TRY THESE OUT !
CaCO3 + 2HCl CaCl2 + CO2 + H2O
Ca(HCO3)2 + 2HCl CaCl2 + 2CO2 +2 H2O

22. Solution of ethanol and glucose will not conduct electricity as
they do not produceions.Non-Electrolytes, strong
electrolytes, weak electrolytes
Acids and base produce ions in the presence of water so they
are able to conductelectricity.
WHAT IS COMMON BETWEEN ALL
ACIDS AND BASES?

23. Acids produce H
+ ions in thepresence ofwater.
HClH
++Cl
‾ (monoproticacid)
4
H
2SO
4 2H
+ + SO
2-(diproticacid)
3
HNO
3 H
+ + NO‾ (monoproticacid)
Hydrogen ion does not exist alone, due to astrong
positive field it combines with a molecule ofwater
and exists as hydronium ion. H
3O
+ is hydrated
hydrogen ion.
H
+ + H
2O H
3O
+ ( Hydroniumion)
IONS PRODUCED BY ACIDS

24. Dry HCl does not show acidicpropertiesasHCl doesnot dissociate into
ions in the absence ofwater.

25. Bases produce OH
-ions in the presence ofwater.
E.gNaOHNa
+ + OH
-
KOHK
+ +OH
-
Ca(OH)
2 Ca
2+ +2OH
-
4
NH
4OH NH
++OH
-
All bases are not soluble in water. Bases thatare
water soluble are calledalkalis
During a neutralizationreaction,
H
+ + OH
-
 H
2O
(from acid) (from base)
IONS PRODUCED BY BASES

26. Acids and bases are highly corrosive so it shouldbe
handledcarefully.
During dilution water should not be added to acid
rather acid should be added to water withconstant
stirring because dissolution of acids is a highly
exothermic process. The heat evolved may cause
the mixture to splash and cause burninjuries.
Temporary heating may also cause the apparatusto
break.
Duringdilutionconcentration of H
+ ions decreases
per unit volume, so the strength of acids will also
decrease.
DILUTION OFACIDS

27. Strong acids dissociate completely in the solution. It will
generate large number of hydrogenions.
Eg. HCl, H
2SO
4, HNO
3,HClO
4
Weak acids dissociate partially in the solution. It will
generate lesser number of hydrogenions.
Eg. CH
3COOH(CH3COO-) +H+, HCOOH,HCN
Strong bases dissociate completely in the solution. It will
generate large number of hydroxideions.
Eg. NaOH, KOH,Ca(OH)
2,Mg(OH)
2
Weak bases dissociate partially in the solution. It will
generate lesser number of hydroxideions
Eg.NH
4OH
STRONG AND WEAK ELECTROLYTES

28. TRY THESE OUT !

29. UNIVERSAL INDICATOR
This indicator is a mixture of many other indicators. The
colourshown by this indicator can be matchedagainst a
pH Scale.
pH = -log [H+]
Potent of hydrogen ion
|---------Acids----------------|Neutral|-----------Bases---------|

30. pHSCALE
Acidic solutions have greater concentrationof hydrogenions.
Basic solutions have greater concentrationofhydroxideions.
pH value less than 7 –Acidic
pH value 7-Neutral
pH value more than 7 -Basic

31. •Plants need optimum pH of the soil for propergrowth
Living organisms can survive in a very narrow range of pH . Due toacid
rain when pH of the water resources decreases , it becomes very difficult
for the survival of aquaticorganisms.
•Our stomach produces hydrochloric acid for the digestion of food. Due to
indigestion stomach produces excess of acid which causes acidity i.e
pain and irritation. By taking Antacids, the excess acid in the stomach
gets neutralized. Milk of magnesia , baking soda solution can be taken
for thispurpose.
•Tooth decay starts when pH of the mouth is less than 5.5. Due to
bacterial action on food remains between the teeth, acids are produced.
These acids will lead to cavities on reaction with enamel(calcium
phosphate). So toothpastes are generally basic in nature which helps to
neutralize the excess acid present in themouth.
IMPORTANCE OF pH IN
EVERYDAY LIFE

32. IMPORTANCE OF pH IN EVERYDAY LIFE
Bee stings/stings by red ants inject methanoic acid into our body
causing pain and irritation. By applying basic substances like baking
soda solution or tooth paste one can get relief from pain as it will
neutralize the effect ofacid.
Stinging hair of nettle leaves also injects methanoic acid. By
applying the extract of dock plants, one can get relief from pain.
Weak acids dissociate partially in the solution. It will generate lesser
number of hydrogenions.

33. Substance Acid
Tamarind Tartaricacid
Lemon,Orange Citricacid
Tomato,Guava Oxalicacid
curd Lacticacid
Antsting Methanoicacid
Nettle leafsting Methanoicacid
Vinegar Aceticacid
apple Malicacid
SOME NATURALLY OCCURING ACIDS

34. TRY THESE OUT !

35. What arethe formulae of the followingsalts?
Potassium sulphate, sodium sulphate,calcium
sulphate, magnesium sulphate, copper sulphate,
sodium chloride, sodium nitrate, sodium carbonate,
ammoniumchloride
Identify the acid and the base from which these salts
have beenderived.
•NaCl-----?
•NH4Cl-----?
SALTS

36. pH OFSALT
Strong acid + Strong base –Neutral salt, pH value is7
E.g. NaCl –NaOH +HCl
Strong acid + weak base –Acidic salt ,pH value is less
than7
E.g.NH
4
Cl-NH
4
OH +HCl
Strong base + weak acid –Basic salt, pH value is more
than7
E.g.CH
3
COONa –CH
3
COOH +NaOH
Sodium acetate

37. Chemical formula:NaOH
Chemicalname:Sodium hydroxide
Common name : Causticsoda
Preparation: It is prepared by passing electricity through
brine( concentrated NaClsolution)
2NaCl +2H
2O 2NaOH +H
2 +Cl
2
The above process is also known as Chlor-alkali process
Chlorine gas is liberated at anode and hydrogen gas atcathode
Uses: NaOH: 1. For making soap, detergents 2. degreasing metals
3. paper making 4. artificialfibers
H
2: For making margarines, as a fuel, for making ammonia for
fertilizers
Cl
2: as a disinfectant, water treatment plants, for making PVC, CFC,
pesticides
SODIUMHYDROXIDE

38. CHLOR-ALKALI PROCESS

39. Chemical formula:CaOCl
2
Chemical name: Calcium oxy chloride
Preparation: By carrying out reactionbetween
slaked lime and chlorinegas.
Ca(OH)
2
+ Cl
2
CaOCl
2
+H
2
O
Uses:1. For bleaching cotton , linen in textile
industry.
2.As an oxidation agent in chemicalindustries
3.Fordisinfectingwater
BLEACHING POWDER

40. Chemical formula:NaHCO
3
Chemical name: Sodium bicarbonate
Preparation: Solvay’sprocess
Raw materials required: NaCl, CO
2, H
2O,NH
3
NaCl + CO
2+H
2O+ NH
3
NaHCO
3 +NH
4Cl
Uses: 1. Baking soda is used to prepare baking powder. Baking powder
is a mixture of baking soda and tartaric acid. Tartaric acid neutralizes
the effect of sodium carbonate formed during thereaction.
2. It is used for making cakes and breads soft and spongy
2NaHCO
3( heat)Na
2CO
3 + H
2O +CO
2
CO2 released makes the cake soft andfluffy
3. Being basic in nature , baking soda solution is used as an antacid.
It neutralizes the excess present in thestomach.
4. For making soda acid fireextinguisher
BAKING SODA

41. Chemical formula:Na
2
CO
3
.10H
2
O
Chemical name : Sodium carbonate decahydrate
Preparation:Sodium hydrogen carbonate obtained by
Solvay’s process when heated gives sodiumcarbonate.
Recrystallisationof sodium carbonate gives washing soda.
Na
2
CO
3
+ 10 H
2
O Na
2
CO
3
.10H
2
O
Uses:1. Used in glass, soap and paperindustry.
2. For removing permanent hardness ofwater.
(Permanent hardness cannot be removed byboiling)
3. As a cleansing agent for domesticpurpose
4. For makingBorax.
WASHING SODA

42. Chemical formula: CaSO
4
.1/2H
2
O
Chemical name: Calcium sulphate hemihydrate
Preparation: By controlled heating of Gypsum (100 C)
CaSO
4
.2H
2
O CaSO
4
.1/2 H
2
O +3/2H
2
O
Gypsum(100C) P.O.P
Uses:1.Formakingtoys,decorativeitems,falseceiling
2.Forsupportingfracturedbones.
3.Formakingunevensurfacessmoothduringpaintingofwalls.
OnaddingwaterP.O.Pcombineswithwaterandformsgypsumagain.
CaSO
4
.1/2 H
2
O + 3/2H
2
O CaSO
4
.2H
2
O
PLASTER OFPARIS

43. Water of crystallization is the fixed number of water molecules present
in one formula unit of a salt.
E.g. CuSO
4
.5H
2
O, FeSO
4
.7H
2
O,Na
2
CO
3
.10H
2
O,CaSO
4
.1/2H
2
O
Uponheatingbluecolouredcrystalsofcoppersulphate,itturns
whiteduetolossofwaterofcrystallization.
WATER OFCRYSTALLISATION

44. TRY THESE OUT !