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consider the following chemical reaction of bromothymol blue indicator.…

Question

consider the following chemical reaction of bromothymol blue indicator. it appears yellow in undissociated form and blue in its dissociated aqueous solution.
\\\ce{hc_{2}h_{3}o_{2}(aq) \
ightleftharpoons h^{+}(aq) + c_{2}h_{3}o_{2}^{-}(aq)} \\
\quad\quad\quad\quad\quad yellow \quad\quad\quad\quad\quad\quad\quad\quad blue

what will be the color of the solution if a large amount of \\(\ce{h_{2}co_{3}}\\) is added?
\\(\bigcirc\\) the solution will remain yellow.
\\(\bigcirc\\) the solution will turn blue.
\\(\bigcirc\\) the solution will turn pink.
\\(\bigcirc\\) the solution will turn green.

Explanation:

Brief Explanations
  1. First, recall the properties of \( \ce{H2CO3} \): Carbonic acid (\( \ce{H2CO3} \)) is an acid, and in aqueous solution, it dissociates to produce \( \ce{H+} \) ions (\( \ce{H2CO3(aq)

ightleftharpoons H+(aq) + HCO3-(aq)} \), and further dissociation of \( \ce{HCO3-} \) also produces \( \ce{H+} \)).

  1. Now, look at the given equilibrium for bromothymol blue: \( \ce{HC2H3O2(aq)

ightleftharpoons H+(aq) + C2H3O2-(aq)} \) (yellow form on the left, blue form on the right).

  1. According to Le Chatelier's principle, when we add a large amount of \( \ce{H2CO3} \), the concentration of \( \ce{H+} \) ions in the solution increases significantly.
  2. An increase in \( \ce{[H+]} \) will shift the equilibrium of the bromothymol blue reaction to the left (because the system tries to counteract the increase in \( \ce{H+} \) by consuming it, so the reverse reaction is favored).
  3. Shifting the equilibrium to the left means more of the undissociated (yellow) form \( \ce{HC2H3O2} \) is present, so the solution will remain yellow (or become more yellow - dominated, but since it was likely in some equilibrium before, adding \( \ce{H+} \) pushes it left). The options of pink or green are not related to the given indicator's color change (bromothymol blue is yellow or blue, not pink/green), and turning blue would require the equilibrium to shift right (which would happen with a base, not an acid adding \( \ce{H+} \)).

Answer:

A. The solution will remain yellow.