Question

b. Draw the Lewis structure of malic acid (the above structure is a skeletal structure, where each "Intersection is a Catom). Also identify the acidic proton (s). (2 points) c. Design an experiment to accurately measure the tartness of the candy. (3 pt)

Answer 1

b. The Lewis structure of Malic Acid is given below-

The acidic protons are marked with red.

LÖCH2-a04) H :0 ! Malic acid

c. To accurately measure the tartness or the amount of acid present in candy,

• take 2 or 3 candies and crush them in mortar.
• dissolve them into 100mL distilled water and shake well
• notice that the mixture is little cloudy! To solve this problem, filter the solution in vacuum filtration to get the acid solution (A). The next task is to prepare the base solution. Here we will take NaOH.
• First, standardize the NaOH using KHP as the primary standard to report the strength of the base. Here, we will use the Phenolphthalein indicator.
• As soon as the concentration of base(
  SNOH
  ) is known, take the NaOH in the burette (do not forget to rinse the burette with the same NaOH you are going to use), and take a known amount of the solution (A) you prepared in a volumetric flask, take $V_{A}$ amount of solution A.
• The suitable indicator for this titration can be Thymol blue which will turn BLUE indicating the endpoint of the titration.
• Record the volume of NaOH used, say
  VNAOH
  .
• Now, calculate the strength of the acid, $S_{A}$ using the
  VNAOH.S Ngoh = VASA
  equation.
• You just accurately measured the tartness of the candy!