Give a balanced chemical equation for each of the following.
1. Combination reaction
2. Decomposition reaction
3. Displacement reaction
4. Double displacement reaction
5. Photochemical reaction
6. Calcination
7. Roasting
8. Precipitation reaction
9. Neutralization reaction
10. Enzyme reaction
11. Positive catalytic reaction
12. Negative catalytic reaction
Answers
Ans:
Displacement reaction :
A single-displacement reaction, also known as a single-replacement reaction, is a reaction by which one
(or more) element(s) replaces an/other element(s) in a compound. It can be represented generally as:
A+B−C→A−C+B
All simple metal with acid reactions are single displacement reactions. For example, the reaction
between magnesium, Mg, and hydrochloric acid, HCl, forms magnesium chloride, MgCl
2
, and hydrogen,
H
2
.
Mg(s)+2HCl(aq)→MgCl
2
(aq)+H
2
(g)
Decomposition reaction :
A decomposition reaction is a type of chemical reaction where one reactant yields two or more
products.
The general form for a decomposition reaction is
AB→A+B
Water can be separated by electrolysis into hydrogen gas and oxygen gas through the decomposition
reaction: 2H
2
O→2H
2
+O
2
Another example is the spontaneous decomposition of hydrogen peroxide into water and oxygen: 2
H
2
O
2
→2H
2
O+O
2
The decomposition of potassium chlorate into potassium chloride and oxygen is yet another example:
2KClO
3
→2KCl+3O
2
Combination reaction :
A combination reaction (also known as a synthesis reaction) is a reaction where two or more elements
or compounds (reactants) combine to form a single compound (product). Such reactions may be
represented by equations of the following form : X+Y→XY.
Formation of calcium oxide by the combination elements calcium and oxygen.
2Ca+O
2
→2CaO
Formation of ammonia by the combination of elements nitrogen and hydrogen.
N
2
+3H
2
→2NH
3
hope it helps..