Question
Explain Hill’s reaction.
✓
Answer
Robert Hill proved that the source of oxygen evolved during photosynthesis is water and not carbon dioxide. Hence, it is called Hill’s Reaction.
$1.$ In this experiment, Hill cultured isolated chloroplasts in a medium containing $CO_2$ free water, haemoglobin and ferric compound.
$2.$ Ferric salts and haemoglobin were added in the medium as hydrogen and oxygen acceptors respectively.
$3.$ When the suspension was illuminated, he observed that haemoglobin turned into oxyhaemoglobin (red colour).
$4.$ This confirmed that water must have oxidized releasing $O_2,$ that reacted with haemoglobin. Reduction of ferric compound was also indicated by change in colour.
$5.$ The $H_2O$ molecule oxidized to evolve $O_2$ as a by$-$product. Thus, Hill proved that the source of evolving $O_2$ is $H_2O$ and not $CO_2.$
$6.$ This process of splitting up of water molecules under the influence of light in the presence of chlorophyll is called Photolysis of water or Hill Reaction.
$1.$ In this experiment, Hill cultured isolated chloroplasts in a medium containing $CO_2$ free water, haemoglobin and ferric compound.
$2.$ Ferric salts and haemoglobin were added in the medium as hydrogen and oxygen acceptors respectively.
$3.$ When the suspension was illuminated, he observed that haemoglobin turned into oxyhaemoglobin (red colour).
$4.$ This confirmed that water must have oxidized releasing $O_2,$ that reacted with haemoglobin. Reduction of ferric compound was also indicated by change in colour.
$5.$ The $H_2O$ molecule oxidized to evolve $O_2$ as a by$-$product. Thus, Hill proved that the source of evolving $O_2$ is $H_2O$ and not $CO_2.$
$6.$ This process of splitting up of water molecules under the influence of light in the presence of chlorophyll is called Photolysis of water or Hill Reaction.
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