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02/11/2019

What is the purpose of iodine clock reaction?

What is the purpose of iodine clock reaction?

The “clock reaction” is a reaction famous for its dramatic colorless-to-blue color change, and is often used in chemistry courses to explore the rate at which reactions take place. The color change occurs when I2 reacts with starch to form a dark blue iodine/starch complex.

What happens during the iodine clock reaction?

Two colorless liquids are mixed together and after a few moments the mixture turns a dark blue color. There are actually a couple of simple chemical reactions going on at the same time to make this “clock reaction” occur.

What is meant by clock reaction?

A chemical clock (or clock reaction) is a complex mixture of reacting chemical compounds in which the onset of an observable property (discoloration or coloration) occurs after a predictable induction time due to the presence of clock species at a detectable amount.

Why does the clock reaction work?

The main assumption is that the blue color is trapped or hidden by the bags. In an iodine clock reaction, the blue color is due to the starch–iodine complex, but the compound that is “trapped” by thio sulfate ions is iodine itself, which is reduced back to colorless iodide ions.

Why is it called iodine clock?

The iodine clock reaction is a favorite demonstration reaction in chemistry classes. The reaction is called a clock reaction because the amount of time that elapses before the solution turns blue depends on the concentrations of the starting chemicals.

What is the order of iodine clock reaction?

The rate of reaction is first-order in potassium iodine.

How does an iodine clock reaction work?

The iodine clock reaction times how long it takes for a fixed amount of thiosulphate ions to be used up, i.e. the time taken for the iodide ions to reach a fixed number of moles produced in the reaction between potassium iodide and an oxidising agent (usually hydrogen peroxide, or sodium peroxodisulphate).

How does a clock reaction work?

A chemical clock (or clock reaction) is a complex mixture of reacting chemical compounds in which the onset of an observable property occurs after a predictable induction time. In cases where one of the reagents has a visible color, crossing a concentration threshold can lead to an abrupt color change after a reproducible time…

What is iodine clock?

“Iodine Clock” refers to a group of reactions which involve the mixing of two colorless solutions to produce a solution which remains colorless for a precise amount of time, then suddenly changes to a deep purple-blue color. The time is controlled by the temperature and/or the concentrations of the reactants.