<Dl> <Dd> C H + HCl → CH = CHCl </Dd> </Dl> <Dd> C H + HCl → CH = CHCl </Dd> <P> For this application, the mercuric chloride is supported on carbon in concentrations of about 5 weight percent . This technology has been eclipsed by the thermal cracking of 1, 2 - dichloroethane . Other significant applications of mercuric chloride include its use as a depolarizer in batteries and as a reagent in organic synthesis and analytical chemistry (see below). It is being used in plant tissue culture for surface sterilisation of explants such as leaf or stem nodes . </P> <P> Mercuric chloride is occasionally used to form an amalgam with metals, such as aluminium . Upon treatment with an aqueous solution of mercuric chloride, aluminium strips quickly become covered by a thin layer of the amalgam . Normally, aluminium is protected by a thin layer of oxide, thus making it inert . Once amalgamated, aluminium can undergo a variety of reactions . For example, it will dissolve in water (this can be dangerous, as hydrogen gas and heat are generated). Halocarbons react with amalgamated aluminium in the Barbier reaction . These alkylaluminium compounds are nucleophilic and can be used in a similar fashion to the Grignard reagent . Amalgamated aluminium is also used as a reducing agent in organic synthesis . Zinc is also commonly amalgamated using mercuric chloride . </P>

Role of mercuric chloride in plant tissue culture