acid bases and salt class 7

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CHAPTER - 4ACIDS, BASES, AND SALTS

• CLASS - VII
• MADE BY - RAVI PRAKASH
  SINGH
• SUBJECT - CHEMISTRY

RAVI PRAKASH SINGH
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ACIDS

• Acids are substances that release hydrogen ions
  when added to water
• H1 H2O ? H3O1
• for example HCl or H2SO4
• Substances that taste sour are called Acidic
  Substances.
• For example lemon, curd, pickles, orange juice,
  vinegar, etc.

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What is an ACID?

• pH less than 7

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COMMON ACIDS USES

• HCl- hydrochloric- stomach acid
• H2SO4- sulphuric acid - car batteries
• HNO3 nitric acid - explosives
• HC2H3O2- acetic acid - vinegar
• H2CO3-carbonic acid sodas
• H3PO4- phosphoric acid -flavorings

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TYPES OF ACIDS

• Acids are of two types
• Mineral Acids
• The acids which are prepared from the mineral
  present in earth are called Mineral acid.
• Ex- Hcl, Kcl, H2SO4, HNO3
• Organic Acids
• The acids which are naturally occurs and found
  in plants animals are called organic acid.
• Ex- Guava contains oxalic acid, lemon contain
  citric acid
• Dilute acids-
• The acids having a low concentration are called
  dilute acid
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

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PROPERTIES OF ACID?

• Tastes Sour
• pH less than 7
• Neutralizes bases
• Forms H ions in solution
• Turns blue litmus paper red.
• Good conductors of electricity
• React with metals to produce hydrogen
• 2HCl 2Na ? 2NaCl H2

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BASES

• Bases are substances that release hydroxide ions
  when added to water
• For example NaOH, or KOH
• Substances that taste bitter are called Basic
  substances.
• For Example - soap or soap solution, baking
  soda, washing soda, etc.

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COMMON BASES USES

• NaOH - sodium hydroxide - soaps, drain cleaner
• Mg (OH)2 - magnesium hydroxide - antacids
• Al(OH)3 -aluminum hydroxide - antacids,
  deodorants
• NH4OH - ammonium hydroxide - ammonia

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PROPERTIES OF BASE?

• Tastes Bitter
• pH greater than 7
• Feels slippery
• Usually forms OH- ions in solution
• Neutralizes acids
• Conducts Electricity
• Turns red litmus paper blue.
• Turns turmeric paper to red.

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PROPERTIES OF BASES

• Bases react with fats to form soap and glycerol.
  This process is called saponification.
• Bases have a pH of more than 7.
• Dilute solutions of bases taste bitter.
• Bases turn phenolphthalein to PINK, litmus to
  BLUE
• Bases neutralize acids.
• Bases are formed when alkali metals or alkaline
  earth metals react with water. The words
  alkali and alkaline mean basic, as opposed
  to acidic.

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INDICATORS

• Indicators are substances that show different
  colors in an acidic and a basic medium.

ACIDIC
NEUTRAL
BASIC
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TYPES OF INDICATOR

• Indicators can be divided into two types.
• Natural Indicator Indicators that are obtained
  from naturally occurring substance are called
  NATURAL INDICATORS. For example litmus,
  turmeric, china rose, etc.
• Synthetic Indicator Indicators that are made in
  laboratory are called SYNTHETIC INDICATORS. For
  example phenolphthalein, methyl orange, etc.

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INDICATORS.
S.No. Indicator Color in strong acidic solution pH at which color change Color in strong alkaline solution
1 Methyl orange Red 4 Yellow
2 Bromothymol blue Yellow 7 Blue
3 Phenolphthalein Colorless 9 Red
4 Screened methyl orange Red 4 Green
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pH Scale
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pH of Common Substances
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pH paper

• pH paper changes color to indicate a specific pH
  value.

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NEUTRALIZATION REACTION

• Reaction of an acid a base to produce salt and
  water is called NEUTRALIZATION REACTION.
• Example
• H2SO4 NaOH ? NaHSO4 H2O
• NaOH HCL ? NaCl H2O
• 2KOH H2SO4 ? K2SO4 2H2O
• Mg(OH)2 2HNO3 ? Mg(NO3)2 2H2O
• The products of a neutralization reaction are a
  salt and water

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SALTS

• A Salt is a compound formed from the positive
  ions of a base and a negative ion of an acid.
• For example NaCl, K2SO4 , KCl, MgSO4, Na3PO4
• Salt are the product of a reaction between an
  acid and a base, along with water.

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PHYSICAL PROPERTIES OF SALTS

• They form crystals when in solid form
• They usually have a higher hardness because of
  their ionic bonding.
• An acid plus a base yields a salt and water.
• HCl NaOH ? NaCl HOH
• or
• HCl NaOH ? NaCl H2O

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NAMING OF SALTS

• The salts of different acids are as follows
• Salts of sulphuric acid (H2SO4) are named as
  sulphates.
• Salts of hydrochloric acid (HCL) are named as
  chlorides.
• Salts of nitric acid (HNO3) are named as
  nitrates.
• Salts of sulphurous acid (H2SO3) are named as
  sulphites.
• Salts of carbonic acid (H2CO3) are named as
  carbonates.
• Salts of acetic acid (CH3COOH) are named as
  acetates.
• Salts of phosphoric acid (H3PO4) are named as
  phosphates.

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TYPES OF SALTS

• Neutral Salt or Normal Salts
• Salt formed by reaction between strong acid and
  strong base are called NEUTRAL SALT
• EXAMPLE- NaOH, KCL, KNO3, ETC.
• HCl(aq) NaOH(aq) ? NaCl(aq)
  H2O(l)
• H2SO4(aq) ZnO(aq) ? ZnSO4(aq)
  H2O(l)
• Normal salts are neutral to litmus paper.

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ACIDIC SALTS

• Salt formed by reaction between Strong Acid and
  Weak Base are called ACIDIC SALT
• H2SO4(aq) KOH(aq) ? KHSO4(aq)
  H2O(l)
• H3PO4(aq) NaOH ? NaH2PO4(aq)
  H2O(l)
• H3PO4(aq) 2NaOH(aq) ? Na2HPO4(aq)
  2H2O(l)
• An Acid salt will turn BLUE litmus RED.

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BASIC SALTS

• Salt formed by reaction between Weak Acid and
  Strong Base are called BASIC SALT
• Zn(OH)2(s) HCl(aq) ? Zn(OH)Cl(aq)
  H2O(l)
• Zn(OH)Cl(aq) HCl(aq) ? ZnCl2(aq)
  H2O(l)
• Mg(OH)2(s) HNO3(aq) ?
  Mg(OH)NO3(aq) H2O(l)
• Mg(OH)NO3(aq) HNO3(aq) ?
  Mg(NO3)2(aq) H2O(l)
• A Basic salt will turn RED litmus BLUE

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