Question

Name the compound used in black and white photography. State whether the reaction that occurs is exothermic or endothermic. Give justification for your answer.

Answer 1

The primary compounds in black and white photography are silver chloride (AgCl) and silver bromide (AgBr).The reaction involved is a photochemical decomposition, classified as endothermic.Explanation:Light absorption triggers the decomposition of silver chloride (or silver bromide) into silver and chlorine (or bromine). For instance:\[ \text{2AgCl(s)} \xrightarrow{\text{Sunlight}} \text{2Ag(s) + Cl}_2\text{(g)} \]Because light energy is necessary for the reaction, it is endothermic. The process absorbs energy (light) to break the bonds within AgCl.\[Compound: Silver Chloride (AgCl) or Silver Bromide (AgBr).
Reaction: Endothermic.
Justification: Light energy is a requirement for decomposition.\]