Exothermic reaction, definition reversible

The term lime also has a broad coimotation and frequently is used in referring to limestone. According to precise definition, lime can only be a burned form quicklime, hydrated lime, or hydraiflic lime. These products are oxides or hydroxides of calcium and magnesium, except hydraiflic types in which the CaO and MgO are chemically combined with impurities. The oxide is converted to a hydroxide by slaking, an exothermic reaction in which the water combines chemically with the lime. These reversible reactions for both high calcium and dolomitic types are Quicklime... 

The arguments advanced in Sect. 3.2.3 apply equally well to a continuous stirred tank reactor. With a reversible exothermic reaction and a fixed mean residence time, t, there is an optimum temperature for operation of a continuous stirred tank reactor. Since the conditions in an ideal stirred tank are, by definition, uniform, there is no opportunity to employ a temperature gradient, as with the plug-flow reactor, to achieve an even better performance. 

Some quite interesting conclusions can be drawn from these values. The major conclusion is that many ions that are usually thought to be good nucleophiles are poor by this definition. For example, RO- reacts readily because its reactions are usually very exothermic (especially with CH3Br). As in solution, RO- cannot undergo reversible displacement in the gas phase. Thus, the inertness of ethers to displacement reactions is a consequence of... 

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