Download CH 1 CHEMICAL REACTIONS AND EQUATIONS

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CHAPTER 1 : Chemical Reactions and Equations
Key Points and Concepts
 A complete chemical equation represents the reactants, products, conditions of reactions and their
physical states symbolically.
 Oxidation : loss of electrons.
 Reduction : gain of electrons.
Important Equations
 Types of Reactions :
S.
No.
1.
2.
3.
4.
5.
6.
Name and Definition
Example
In a combination reaction, two or
more reactants combine to give a single product.
In a decomposition reaction, a single
reactant breaks down into two or
more simpler products.
When decomposition reaction is
carried out by heating, it is called
thermal decomposition reaction.
CaO(s)
(Quick lime)
(Lead nitrate)
In a displacement reaction, a more
reactive element displaces a less
reactive element from a compound.
H2O(l) → Ca(OH)2(aq)
(water)
2Pb(NO3)2 Heat
→
→
(Calcium carbonate)
2H2O(l)
Fe(s)
(Oxygen)
CaO(s) + CO2(g)
(Quicklime)
Sunlight
→ 2Ag(s)
+
Br2(g)
(Silver)
Electric current
→ 2H2(g)
(Water)
(Iron)
+ O2(g)
(Nitrogen dioxide)
Heat
CaCO3(s)
(Slaked lime)
2PbO(s) + 4NO2(g)
(2PbO)
When decomposition reaction is
2AgBr(s)
carried out in the presence of sunlight,
(Silver bromide)
the process is called photochemical decomposition.
Electrolysis : When decomposition
reaction is carried out with the help
of electric current, the process is
called electrolysis.
+
(Bromine)
+
(Hydrogen gas)
+
CuSO4(aq)
(Copper sulphate)
→ FeSO4(aq)
(Iron sulphate)
O2(g)
(Oxygen gas)
+ Cu(s)
(Copper)
On Tips Notes
7.
9
Na2SO4(aq) + BaCl2(aq) → BaSO4(s) + 2NaCl(aq)
The reactions in which two different
atoms or groups of atoms are
displaced by other atoms or groups of
atoms, i.e., two compounds exchange
their ions and one of the products
formed is insoluble, are said to be
double displacement reactions.
8.
(Sodium
sulphate)
The reactions in which acid or acidic
oxide reacts with the base or basic
oxides to form salt and water are
called neutralization reactions.
(Barium
chloride)
2NaOH +
(Sodium
hydroxide)
(Barium
sulphate)
(Sodium)
chloride)
H2SO4 → Na2SO4 + 2H2O
(Sulphuric
acid)
(Sodium
sulphate)
(Water)
 Some usually asked equations in exams for balancing :
2CO(g)
l
+
(Carbon monoxide)
→
O2(g)
(Oxygen)
2CO2(g)
(Carbon dioxide)
Heat
l
l
l
→
ZnCO3
ZnO + CO2
2FeSO4(s) → Fe2O3(s) + SO2(g) + SO3(g)
Pb(NO3)2 +
2KI
→ 2KNO3 +
(Lead nitrate)
l
CaO(s)
(Quick lime)
l
l
NaCl
(Sodium
chloride)
(Potassium
iodide)
+ H2O →
(Potassium
nitrate)
Ca(OH)2
PbI2
(Lead Iodide)
+ Heat
(Slaked lime)
+ AgNO3 →
(Silver
nitrate)
AgCl
+ NaNO3
(Silver
chloride)
(Sodium
nitrate)
Ca + 2HNO3 → Ca(NO3)2 + H2 ↑
l Mg + 2HNO3 → Mg(NO3)2 + H2 ↑
l
2Al + 3H2SO4 → Al2(SO4)3 + 3H2 ↑
l
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
l
Ca(OH)2 + CO2 → CaCO3 + H2O
l
Zn + H2SO4 → ZnSO4 + H2 ↑
l
Zn + 2HCl → ZnCl2 + H2 ­↑
l
4Zn + 10HNO3 → 4Zn(NO3)2 + 5H2O + N2O
l
Zn + 2NaOH
Heat
→ Na2ZnO2 + H2 ↑
 Redox (Oxidation and Reduction) Reaction :
Oxidation (HCl is oxidized)
MnO2 (s) +4HCl (conc.)
MnCl 2(aq) +Cl 2(g) + 2H 2O
Reduction (MnO2 is reduced)

CHAPTER 2 : Acids, Bases and Salts
Key Points and Concepts
 Those substances which turn blue litmus solution into red are called acids. Acids are sour in taste. They
give H+ ions in aqueous solution. e.g. :
HCl, H2SO4, HNO3, CH3COOH