Hi. I'm trying to replicate your experiment right now. Here is an hypothesis on what is going on: When the reaction starts, the pH of the solution is alkaline. However, as the hypochlorite is reduced to chlorine gas and then chloride ions, the pH of the solution changes towards neutral. **There's a chemical equilibrium here** like this: chlorine gas + water hydrochloric acid + hypochlorous acid Notice that an alkaline pH is required to more this equilibrium to the right side which has the hypochlorite ion. Thus, the baking soda acts as the base that moves the reaction to the other side, preventing the oxidation agent (chlorine gas) to escape and making the copper to become fully oxidized and the hypochlorous ion to be fully reduced to chloride.
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Hi. I'm trying to replicate your experiment right now. Here is an hypothesis on what is going on:
When the reaction starts, the pH of the solution is alkaline. However, as the hypochlorite is reduced to chlorine gas and then chloride ions, the pH of the solution changes towards neutral. **There's a chemical equilibrium here** like this:
chlorine gas + water hydrochloric acid + hypochlorous acid
Notice that an alkaline pH is required to more this equilibrium to the right side which has the hypochlorite ion. Thus, the baking soda acts as the base that moves the reaction to the other side, preventing the oxidation agent (chlorine gas) to escape and making the copper to become fully oxidized and the hypochlorous ion to be fully reduced to chloride.
copper carbonate probably!