1. M RS. A NTARA D AS M RS. S USHMA S URESH

2. The word ‘Acid’ came from Latin word ‘Acidus or Acere’ which means sour.

4. A CIDS ARE DERIVED FROM MINERALS AS WELLS AS PLANTS.

5. Urtica dioica, often called common nettle or stinging nettle

6. HC L + H 2 O → H + + C L - H 2 SO 4 + H 2 O → 2H + + SO 4 - An acid is a compound which when dissolved in water yields hydrogen ion as the only positvely charged ions.

7. B ASICITY OF A CID It is the number of ionizable H + ions present in an acid. HCl is mono basic, it ionizes to produce one H + ion HCl  ==============  H + + Cl - H 2 SO 4 is Dibasic, It ionizes to produce two H + ions. H 2 SO 4  ===============  2H + + SO 4 2- H 3 PO 4 is Tribasic, it ionizes to produce three H + ions. H 3 PO 4  ==============  3H + + PO 4 3-

8. C HEMICAL P ROPERTIES OF A CIDS With metals Metals above copper in the reactivity series will react with acids, giving off hydrogen gas, forming a salt. Mg (s) + H 2 SO 4(aq)  MgSO 4(aq) + H 2(g) With bases (metal oxides and hydroxides) The base dissolves in the acid and neutralises it. A salt is formed. H 2 SO 4(aq) + CuO (s)  CuSO 4(aq) + H 2 O (l) With metal carbonates With metal carbonates, effervescence occurs, salt, water and carbon dioxide gas is produced. 2HCl (aq) + CaCO 3(s)  CaCl 2(s) + H 2 O (l) + CO 2(g)

10. An alkali is a compound which when dissolved in water yields hydroxyl ion as the only negatively charged ions. NaOH + H 2 O → Na + + OH - Ca(OH) 2 + H 2 O → Ca +2 + OH -

11. A CIDITY OF A B ASE It is the ionizable OH - ions present in an alkali. e.g. NaOH is monoacidic NaOH  ==========  Na + + OH - Ca(OH) 2 is diacidic Ca(OH) 2  =========  Ca 2+ + 2OH -

12. O CCURRENCE OF BASES NaOH Soaps and drain cleaner. Mg (OH) 2 antacids. Al(OH) 3 antacids, deodorants. KOH alkaline batteries of car.

13. Neutralisation reaction. NaOH + HCl ==> NaCl + H 2 O Ammonium salts are decomposed when mixed with a base. NaOH + NH 4 Cl ==> NaCl + H 2 O + NH 3 Alkali's are used to produce the insoluble hydroxide precipitates of many metal ions from their soluble salt solutions. 2NaOH (aq) + CuSO 4(aq) ==> Na 2 SO 4(aq) + Cu(OH) 2(s) C HEMICAL P ROPERTIES OF B ASES

14.  Acids taste sour.  Aqueous solutions of all acids contain hydrogen ions.  Acid turns blue litmus red.  Strong acids are corrosive.  Alkalis taste bitter  Aqueous solutions of all alkalis contain hydroxide ion.  Alkalis turns red litmus blue.  Soapy to touch AcidsBases

15. R EACTIONS WITH INDICATORS IndicatorAcid color Neutral color Base color PhenolphthaleinColorlessFaint pinkDark pink Bromthymol blue YellowGreenBlue LitmusRed-----Blue

16. N EUTRALIZATION R EACTION A neutralization reaction is the reaction of an acid with a base to produce salt and water. H 2 SO4 + NaOH  NaHSO 4 + H 2 O

17. When H + ion of an acid is replaced by a metal ion, a salt is produced. H 2 SO 4 + 2NaOH ===  Na 2 SO 4 + 2H 2 O Examples: KCl, MgSO 4, Na 3 PO 4 S ALTS

18. T YPES OF S ALTS Normal Salts: Normal salts are formed when all the replaceable hydrogen ions in the acid have been completely replaced by metallic ions. HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O (l) H 2 SO 4(aq) + ZnO (aq)  ZnSO 4(aq) + H 2 O (l) Normal salts are neutral to litmus paper.

19. Acid salts: Acid salts are formed when replaceable hydrogen ions in acids are only partially replaced by a metal. H 2 SO 4 + KOH  KHSO 4 + H 2 O

20. Basic Salts: Basic salts contain the hydroxide ion, OH-. They are formed when there is insufficient supply of acid for the complete neutralization of the base. A basic salt will turn red litmus blue and will react with excess acid to form normal salt. Zn(OH) 2(s) + HCl (aq)  Zn(OH)Cl (aq) + H 2 O (l)

21. H YDRATED AND ANHYDROUS SALTS : Hydrated Salt: Salt that contains Water of Crystallization is called Hydrated Salt. e.g. CuSO 4.5H 2 O, Na 2 CO 3.10H 2 O. Anhydrous Salt: Salt with out Water of Crystallization is called Anhydrous Salt. e.g. CuSO 4, Na 2 CO 3

23. P H PAPER pH paper changes color to indicate a specific pH value.

24. T HE P H S CALE

26. USES OF SALTS S.NoSALTUSE 1Ammonium ChlorideIn torch batteries 2Ammonium NitrateIn fertilizers 3Calcium ChlorideAs drying agent 4Iron SulphateIn Iron tablets 5Magnesium SulphateIn medicine 6Potassium NitrateIn gunpowder etc. 7Silver BromideIn photography 8Sodium ChlorideMaking NaOH 9Sodium StearateIn making soap.

27. T HE END