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

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.

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

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.