Question

equilibrium lab analysis questions: use what you learned in this lab to answer the following questions in complete sentences. 1. bromthymol blue, BTB is an acid which has a hydrogen ion, H+. for purposes of this question you will write it HBTB. HBTB ionizes in water to produce hydrogen ion, H+, and bromthymol blue ion, BTB-.a) what color appeared when you added HCL to BTB? b) what color appeared when you added NaOH? c) explain the shift in equilibrium in terms of le chatelier's principle

Answer 1

Answer:

See below  

Explanation:

a) Adding HCl

HBTB is yellow in acid solution.

b) Adding NaOH

HBTB is blue in basic solution.

c) Explanation

HBTB is a weak acid in which the undissociated and ionized forms have different colours.

$\underbrace{\hbox{\text{HBTB }}}_{\hbox{\text{yellow}}} + \text{{ H _{2} O}}\rightleftharpoons \text{H _{3} O ^{+} } +\underbrace{\hbox{\text{ BTB ^{-} }}}_{\hbox{\text{blue}}}$

Around pH 7 , the indicator consists of roughly equal amounts of the yellow and blue forms, so it appears green

According to Le Châtelier's Principle, if you apply a stress to a system at equilibrium, it will respond in a way that will relieve the stress.

When you added HCl, you increased the concentration of H₃O⁺. The system responded in a way that would decrease the H₃O⁺. That is, the position of equilibrium shifted to the left and produced more of the yellow form.

When you added NaOH, the base removed some of the H₃O⁺. The system responded in a way that would increase the H₃O⁺. That is, the position of equilibrium shifted to the right and produced more of the blue form