Write 10 examples each of Combination …

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, H₂​.
Mg(s)+2HCl(aq)→MgCl_2​(aq)+H₂(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: 2H₂O → 2H₂ + O₂​
Another example is the spontaneous decomposition of hydrogen peroxide into water and oxygen: 2H₂O₂​ → 2H₂O + O₂​
The decomposition of potassium chlorate into potassium chloride and oxygen is yet another example: 2KClO₃ → 2KCl + 3O₂​

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 + O₂ → 2CaO
Formation of ammonia by the combination of elements nitrogen and hydrogen. N₂ + 3H₂​ → 2NH₃​