Determine the resulting pH when 75 mL of 0.05M HBr is reacted with 74 mL of 0.075 M KOH

pH = 12.08

Explanation:

First we calculate how many moles of each substance were added, using the given volume and concentration:

As HBr is a strong acid, it dissociates completely into H⁺ and Br⁻ species. Conversely, KOH dissociates completely into OH⁻ and K⁺ species.

As there are more OH⁻ moles than H⁺ moles (5.55 vs 3.75), we calculate how many OH⁻ moles remain after the reaction:

With that number of moles and the volume of the mixture, we calculate [OH⁻]:

With [OH⁻], we calculate the pOH:

With the pOH, we calculate the pH:

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e