To determine what would happen if hydrobromic acid (HBr) solution was added to the reaction mixture, we need to consider the possible reactions that could occur.
First, let's write the balanced molecular equation for the reaction between hydrobromic acid (HBr) and sodium hydroxide (NaOH):
HBr (aq) + NaOH (aq) -> NaBr (aq) + H2O (l)
Now, let's consider how this reaction would affect the green, gelatinous precipitate formed earlier. Nickel hydroxide (Ni(OH)2) is an amphoteric substance, meaning it can react with both acids and bases.
In the presence of hydrochloric acid (HCl), the following reaction can occur:
Ni(OH)2 (s) + 2HCl (aq) -> NiCl2 (aq) + 2H2O (l)
Similarly, in the presence of hydrobromic acid (HBr), the following reaction can occur:
Ni(OH)2 (s) + 2HBr (aq) -> NiBr2 (aq) + 2H2O (l)
Therefore, if hydrobromic acid solution is added to the reaction mixture, it would react with the green, gelatinous precipitate (nickel hydroxide) and form a solution of nickel bromide (NiBr2) and water. The green color of the precipitate would likely disappear.
To summarize:
Reaction between HBr and NaOH:
HBr (aq) + NaOH (aq) -> NaBr (aq) + H2O (l)
Reaction between Ni(OH)2 and HBr:
Ni(OH)2 (s) + 2HBr (aq) -> NiBr2 (aq) + 2H2O (l)