A student titrates an unknown weak acid, HA, to a pale pink phenolphthalein endpoint with 25.0 mL of 0.100 M NaOH. The student then titrates in 11.0 mL of 0.100 M HCl to the solution containing the neutralized unknown acid (HCl was delivered from a second buret). The pH of the resulting solution is pH

Hello your question is incomplete the pH of the solution is unknown hence I will take the pH of the solution be = 4.7

answer : Pka = 5   i.e. > 4.7

Explanation:

Student titrates :

Unknown weak acid ( HA ) with 25 mL of 0.100 M of NaOH ( to a pale pink phenolphthalein endpoint )  then titrates with  11.0 mL of 0.100 M HCL to the solution that contains neutralized unknown acid

Assuming pH of solution = 4.7

HA + NaOH --------> H2O + NaA

at equilibrium  point

0.1 * 25 * 1 = n * 1  ∴   = 2.5 mmoles ------ 1

also

 + HCL ---------> HA + C

at equilibrium point

= 1.1 mmoles --------- 2

The ratio of reaction 2 to 1

= 1.1 / 2.5 ≈ 1/2   ( this show that when the pH = 4.7 approximately half of the A^-  have been converted to HA )

Determine the pKa value of the solution

Given that

pH = Pka + log ( A^- / hA )

4.7 = Pka + log ( 1/2 )

therefore Pka = 4.7 - ( -0.3 ) = 5

water   molecules stay close to each other through cohesion, the collective action of hydrogen bonds between water molecules. cohesion plants draw water upwards from the root through the stem's transport tubes (xylem) to the leaf. this transport occurs even in large trees and against gravity. transpiration, evaporation of water from plant leaves, creates a tension on water molecules being pulled up from the stem and roots.

water also has high (the attraction of one substance to another) properties because of its polar nature. adhesion of water molecules to plant cell walls counteract gravity while water is transported from roots to leaves.

water exhibits a very high surface tension when compared to other liquids. surface tension is a property of a liquid that holds the surface together and allows it to resist an external force. by capillary action, the water forms concave menisci inside the pores. the high surface tension of water pulls the concavity outwards, generating enough force to lift water from the roots to the leaves of plants.

thus, cohesion, along with adhesion and surface tension creates a capillary action that keeps water molecules interacting and moving through the plants out to the leaf cells.

therefore, option d) is the correct answer.

explanation:

i think the answer is terrae but not 100 percent sure. ▓▬▬ §