Question

a) Write the essential condition for the following reaction to take place: 2AgBrâ-> 2Ag + Br2 Write one application of this reaction. (b) Complete the following chemical equation of a chemical reaction 2FeS04 â

Answer 1

The given reaction is a photochemical decomposition reacton.

• The essential condition for the reaction to take place is in the presence of sunlight.
• The reaction is the photochemical decomposition reaction which decomposes in the presence of sunlight.
• This reaction is used in black and white photography.

         2AgBr --hν------> 2Ag +Br₂

• 2FeSO₄  --------> Fe₂O₃ +SO₂+SO₃
• It is also a decomposition reaction in which one compound is decomposed to form two or more compounds.

Answer 2

• The components here was silver bromide, silver and bromine gas.
• silver bromide decomposes into silver metal and bromine gas when expose to sunlight.
• Here,since silver  bromide decomposes after getting energy from sunlight ,hence this reaction is called Thermal Decomposition,Decomposition Reaction or Endothermic Reaction.
• AgBr is widely used in photographic films and is believed by some to have used for making shroud of turin.

     b)The chemical reaction of $2FeSO_{4}$ is

• $2FeSO_{4}(s)- - > Fe_{2}O_{3} (s)+SO_{2} (g)+SO_{3} (g)$
• Anhydrous ferrous sulphate on heating gives ferric oxide along with the liberation of sulphur dioxide and sulphur trioxide.

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