Which indicator is commonly used for iodimetry analysis?

In iodimetry analysis, the primary goal is to determine the concentration of iodine and related compounds through redox reactions. Starch is specifically utilized as an indicator in this type of analysis due to its ability to form a complex with iodine. When iodine is present in a solution, it forms a blue-black complex with starch, which is a visual indicator of the presence of iodine in the solution.

The use of starch as an indicator is particularly important because it provides a clear and distinct color change that indicates the endpoint of the titration. When iodine is reduced, the color disappears, marking the completion of the reaction. This characteristic makes starch an ideal choice for iodimetry, allowing for accurate and easy determination of iodine content.

Other indicators like phenolphthalein, litmus, and methyl orange are mainly used for acid-base titrations and do not provide the necessary colorimetric response for iodine detection in iodimetric analyses. Hence, starch stands out as the appropriate indicator in this context, making it the correct choice for iodimetry analyses.