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FA II

ACIDS, BASES AND SALTS

ORAL QUESTIONS – (Conversation Type)



  1. Acids are sour in taste. Is it a way to find whether a substance is an acid or a base?

  2. What is other physical test?

  3. Any test with solid acid?

  4. Can you check the evolution of CO2 chemically?



  1. What are acids?

  2. Can presence of H+ ion in water be estimated? How?

  3. How is pH related to strength of an acid?

  4. Name one strong acid and one weak acid.



  1. What are salts?

  2. How many types of salts are formed?

  3. What are neutral salts?

  4. What do you mean by acidic salts?

  5. Define basic salts.

  6. Give the corresponding acid and base from which sodium carbonate is formed.



  1. What is common salt?

  2. Why does common salt become moist in rainy season?

  3. How is it used as a freezing mixture?

  4. Name two important laboratory chemicals prepared from common salt on large scale.



  1. What is washing soda?

  2. Name the process by which sodium carbonate is manufacture.

  3. What are the raw materials used in the preparation of washing soda?

  4. Sodium carbonate is obtained from another carbonate on heating. Name it.



  1. Name the substance used for bleaching cotton and wood pulp in textiles.

  2. What is its chemical name?

  3. How is it manufactured?

  4. What is slaked lime?

  5. Why does bleaching powder smell of chlorine?

ORAL QUESTIONS



Name the acid present in lemon juice.



What is the chemical difference between washing soda and baking powder?



Name the acid present in ant sting.



What is the ideal pH of the soil for the healthy growth of a plant?



At what pH the mouth teeth start decaying?



How is pH of an acid solution affected when it is diluted?



Name the gas responsible for extinguishing fire in a soda – acid fire extinguisher.



Out of glucose and acetic acid which one will conduct electricity in water?



What is the pH of blood?



What is the chemical name of the compound which has the property of hardening when mixed with water?

QUIZ – WHO AM I



I can roughly measure pH value from 0 – 14.



I am called antichlor and am used to remove excess chlorine from clothes when treated with bleaching powder.



I am a product of gypsum and am used to making chalks and fire proof materials.



I am a compound of calcium and can be used for disinfecting drinking water as well as for decolourisation.



I give different smell in acid and base solution.



I am an oxide capable of showing properties for both acids and bases.



I am a covalent compound and conducts electricity in aqueous medium.



I am a salt of potassium hydroxide and nitric acid.



I am the term used when a solid becomes liquid when exposed to moist air.



I am derived from tomato and turn blue litmus into red.

PUZZLES



Across

  1. Known as vinegar (6)

  1. A mineral acid (12)

Down

  1. Acid obtained from milk (6)

  2. An acid obtained from lemon (6)
















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Across

  1. A stone used for manufacture of sodium carbonate (9)

  1. A substance that changes colour in acid – base solution (9)

Down

  1. A gas obtained in the electrolysis of sodium chloride (8)

  2. A substance that gives relief from acidity (7)






















2C






























































































































































































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3

N










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CHAPTER – 3
METALS AND NON – METALS GIST OF THE LESSON

Elements are classified broadly into two categories on the basis of properties:

Metals: Iron, Zinc, Copper, Aluminium etc.

Non – metals: Chlorine, Nitrogen, Hydrogen, Oxygen, Sulphur etc.

Apart from metals and non-metals some elements show properties of both metals and non – metals,

e.g. Silicon, Arsenic, Germanium .They are called metalloids



Comparison of physical and chemical properties of metals and non – metals:-

Sr. No.

Property

Metals

Non-Metals

1

Physical State

Metals are solid at room temperature. Except mercury and gallium.

Non-metals generally exist as solids and gases, except Bromine.

2

Melting and boiling points

Metals generally have high m.pt and b.pt except gallium and cesium.

Non-metals have low m.pt and b.pt except diamond and graphite.

3

Density

Generally high.

Generally low.

4

Malleability and Ductility

Malleable and ductile.

Neither malleable nor ductile.

5

Electrical and thermal conductivity

Good conductors of heat and electricity.

Generally poor conductors of heat and electricity except graphite.

6

Luster

Poses shining luster.

Do not have luster except iodine.

7

Sonorous sound

Give sonorous sound when struck.

Does not give sonorous sound.

8

Hardness

Generally hard except Na, K

Solid non-metals are generally soft except diamond.


Comparison of Chemical Properties of Metals and Non-metals:-

1

Reaction with Oxygen

Metal + Oxygen Metal oxide

4Na(s) + O2(g)  2Na2O(s)

4Al(s) + 3O2(g)  2Al2O3

Metals form basic oxides Zn and Al form amphoteric oxides (they show the properties of both acidic and basic oxides) Most of the metal oxides are insoluble in water Some of them dissolve to form Alkali Na2O(s) + H2O(l)  2NaOH(aq)



Non-metal + Oxygen  Non-metal oxide C + O2  CO2

S + O2  SO2

Non-metals form acidic oxides CO and H2O are neutral oxides(they are neither acidic nor basic in nature) Non-metal oxides are soluble in water They dissolve in water to form acids SO2 + H2O  H2SO3


2

Reaction with water

Metals react with water to form metal oxides or metal hydroxide and H2 gas is released. 2Na(s) + 2H2O(l)  2NaOH +

H2(g) + heat



Non-metals do not react with water, steam to evolve hydrogen gas. Because Non-metals cannot give electrons to hydrogen in water so that it can be released as H2 gas.

3

Reaction with dilute Acids

Metal + Acid  Metal salt + Hydrogen
HCl Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)

H2SO4 2Na(s) + H2SO4  Na2SO4(aq) +H2(g)

HNO3 Metal + HNO3  H2 gas is not displaced. Reason- HNO3 is strong oxidizing agent.

Non-metals do not react with acids to release H2 gas Reason- Non-metals cannot loose electrons and give it to Hydrogen ions of acids so that the gas is released.

Mn + 2HNO3  Mn(NO3)2 + H2 H2 gas from HNO3



4

Reaction with salt solutions

When metals react with salt solution, more reactive metal will displace a less reactive metal from its salt solution. CuSO4(aq) + Zn(s)  ZnSO4(aq) + Cu(s)

When non-metals react with salt solution, more reactive non-metal will displace a less reactive non-metal from its salt solution. 2NaBr(aq) + Cl2(g)  2NaCl(aq) + Br2(aq)

5

Reaction with Chlorine

Metal + Chlorine  Metal Chloride ionic bond is formed. Therefore Ionic compound is obtained. 2Na + Cl2  2NaCl

Non-metal + Chlorine  Non-metal Chloride covalent bond is formed. Therefore covalent compound is obtained. H2(g) + Cl2  2HCl

6

Reaction with Hydrogen

Metals react with hydrogen to form metal hydride This reaction takes place only for most reactive metals. 2Na(s) + H2(g)  2NaH(s)

Non-metals react with hydrogen to form hydrides H2(g) + S(l)  H2S(g)


Properties of ionic compounds

  1. Physical nature:solid and hard due to strong force of attraction. (generally brittle)

  2. Melting point and boiling point:have high M.P and B.P, as large amount of heat energy is required to break strong ionic attraction.

  3. Solubility: soluble in water and insoluble in kerosene and pertrol.

  4. Conduction of electricity:ionic compounds in solid state-----does not conduct electricity.

Reason—Ions can not move due to rigid solid structure. Ionic compounds conduct electricity in molten state.

Reason-- Ions can move freely since the electrostatic forces of attraction between the oppositely charged ions are overcome due to heat.

Occurrence of metals.

It occurs in Earths crust, sea-water



Minerals

Ores

Elements or compounds, occuring naturally Minerals that contain very high percentage

in the earth’s crust of a perticular metal and these metals can be

extracted economically on a large scale.

e.g Bouxite ore → Aluminium

Haematite → Iron




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