TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: In processes (P1) and (P2), the hydride feed and feed gas are introduced continuously into the reaction vessel and the product gas and effluent are discharged continuously from the reaction vessel. In process (P1), the reaction vessel is not mechanically agitated. In process (P1), the conversion of the hydride is at least 80%; and the conversion of the halosilane is at least 80%. In process (P2), a mechanical agitator (A1) is disposed within the reaction vessel. In process (P2), the agitator (A1) agitates the contents of at least one reaction zone of the vessel, the reaction between the hydride and halosilane in each agitated reaction zone being performed under conditions that approach a continuously ideally-stirred tank reactor. In process (P2), each reaction zone of the reaction vessel is agitated. In process (P2), the reaction mixture is cooled in at least one of the reaction zone. In process (P2), the reaction mixture in the upper reaction zone is cooled; and the reaction mixture in the lower reaction zone is not cooled. In process (P2), the reaction mixture in the intermediate reaction zone is cooled; and the reaction mixture in the lower reaction zone is not cooled. In process (P2), the conversion of the hydride is at least 80 (preferably at least 99)%; and the conversion of halosilane is at least 80 (preferably at least 99)%. In process (P2), the reaction mixture is agitated by gas-phase bubble action. In process (P2), the temperature of the reaction mixture within one of the reaction zone is monitored to control the flow rate of at least one of the hydride feed and feed gas, where the temperature is compared to a temperature, T100, at which 100% conversion is achieved based on the respective reactant flow rates. In process (P2), the difference in temperature between two reaction zones is monitored to control the flow rate of at least one of the hydride feed and feed gas, where the temperature difference is compared to a temperature difference, T Delta , at which 100% conversion is achieved based on the respective reactant flow rates. Preferred Components: The hydride is selected from alkali or alkaline earth metal hydrides and/or alkali or alkaline earth metal salts of aluminum tetrahydride. The halosilane is selected from silicon tetrahalide, trihalosilane, dihalosilane and/or monohalosilane. The hydride is an alkali or alkaline earth metal salt of aluminum tetrahydride (preferably sodium salt of aluminum tetrahydride), the halosilane is silicon tetrahalide preferably silicon tetrafluoride) and the halide salt is an alkali or alkaline earth-metal salt of aluminum tetrahalide (preferably sodium salt of aluminum tetrafluoride). The discharged effluent is a slurry. The hydride feed is a solution that comprises a solvent and a hydride. The hydride feed comprises solid hydride.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The mechanical agitator (A1) is an impeller having at least one blade disposed within each agitated reaction zone. The vessel (V2) comprises an upper inlet in which the hydride feed is introduced, a lower inlet in which the feed gas is introduced, an upper outlet from which the product gas is discharged and a lower outlet from which the effluent is discharged. The reaction vessel (V2) includes a baffle which defines a lower reaction zone and an upper reaction zone. The reaction vessel (V2) includes two baffles which define a lower reaction zone, an intermediate reaction zone and an upper reaction zone. The reaction vessel (V2) is cylindrical and the baffles are annular.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The solvent is selected from polyethers and/or hydrocarbons. The polyethers are selected from diglyme, monoglyme and/or dioxane and the hydrocarbons are selected from toluene and/or pentane. EXAMPLE - No suitable example given.