Question

Hill reaction was demonstrated

• A. in the absence of water
• B. in the absence of carbon dioxide
• C. in the presence of carbon dioxide
• D. in the absence of a suitable electron acceptor

Answer 1

Answer: (B)

Robin Hill (1937) illuminated the isolated chloroplasts of Stellaria media in the presence of leaf extract or hydrogen acceptors (e.g., ferricyanides, chromates, benzoquinones, dichlorophenol, indophenol, etc.) and in the absence of carbon dioxide. The chloroplasts evolved oxygen. The hydrogen acceptors are often called Hill oxidants while the reaction involving the production of oxygen by the illuminated chloroplasts in the absence of $C{O}_2$ fixation is called Hill reaction.