Question

For the Keq lab, there are many differences between solution (C1-C3) and (C4-C6). Is the following description true for C1-C3? C4-C6? or all C1-C6? A) blue in color B) without H+ attached. C) acidic form

Answer 1

What are the differenes bewteen the samples C1-C6

In this experiment, we are to determine the equilibrium constant (K_eq) of the indicator Bromothymol Blue. Bromothymol Blue is blue in the basic form and it turns yellow in the acidic form.

Therefore depending on the nature of the solution (acidic or basic) the color of Bromothymol Blue changes.

Now for the samples C1 to C6, we can refer to the table in Part 1. We see that for the samples C1-C3, we have Bromothymol Blue solutions along with HCl solutions. HCl is a strong acid and dissociated into H+ ions in solution. The presence of the H+ ions reduce the pH of the solution as

pH=-log[H+] where [] indicates concentration.

Therefore in these samples (C1-C3) the Bromothymol Blue is in acidic form and it turns yellow.

For the samples C4-C6, the Bromothymol Blue is taken along with NaOH which is a strong base. A base dissociates into OH- ions and it increases the pH. Therefore tge Bromothymol Blue is blue in color.

Therfore,

A. Blue in color: C4-C6

b. Without H+ attached: C4-C6

c. acidic form: C1-C3