Question

The reaction, $2AgBr\xrightarrow{h\upsilon }2Ag+B{{r}_{2}}$ is an example of:
(A) Photochemical decomposition reaction
(B) Thermal decomposition reaction
(C) Combination reaction
(D) Displacement reaction

Answer 1

To approach this question one should have the basic knowledge of what is chemical reaction. One type of chemical reaction is decomposition reaction in which we observe that the reactants are broken down into minute or small products. The photochemical reaction is one of the subdivisions of decomposition reaction in which the use of light is done for the formation of products.

Complete answer:
In photochemical decomposition reaction the use of a photon or light energy is done for decomposing or breaking the complex structure of the substance into simpler substances. The photons tend to break down and interact with the targeted molecules. In the reaction we see that a reactant gets decomposed into two resultant products. The supply of light is done so that energy is provided for proceeding the reaction. The reactant given in the reaction is silver bromide which is light sensitive and gets decomposed on the exposure of light. So on decomposition it gives silver and bromine. The reaction is the following.
$2AgBr\xrightarrow{h\upsilon }2Ag+B{{r}_{2}}$
The $h\upsilon$ in the reaction indicates that the energy is present of a photon or light. The in thermal decomposition reaction in which the reaction is able to activate by the presence of thermal energy. It requires to supply the energy in the form of heat to the reactants. In combination reactions two or more reactants tend to form a single product. In a displacement reaction in which we see the displacement of an atom or a set of atoms by another atom in a molecule.

Hence the correct answer is (A).

Note: The different chemical reactions are combination, decomposition, combustion, neutralization and displacement reaction. In the combustion reaction we see that oxygen get combined with a compound to form carbon dioxide and water. In the neutralization reaction we see that the acid and a base get reacted to form water and salt.