We have to grade the following text and answer the questions below with a yes or

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We have to grade the following text and answer the questions below with a yes or no. Here are the questions and below the questions will be the text that you have to read.

1. Does the essay contain a topic sentence that introduces the concept of titration?

2. Is the concept of titration described to be a technique where a solution of a known concentration is used to determine the concentration of another solution?

3. Does the essay indicate that the equivalence point is reached when the reaction is complete? (i.e. when the amount of the added titrant is stoichiometrically equal to the analyte?)

4. Does the essay indicate that in a titration the titrant must be a standard solution with an accurately known concentration?

5. Does the essay describe that the equivalence point is determined by recording the volume of titrant added when color change of the indicator persists (or by a rapid change in pH according to a pH meter)?

6. Is the indicator described as a substance able to change color depending on the pH of the solution?

7. Does the essay indicate that the NaOH solution should be standardized before being used as a titrant for HCL?

8. Do the instructions clearly state that an indicator is added to the HCl solution before the titration begins?

9. Does the essay provide a reason, such as a change in concentration over time, that would necessitate a standardization of the titrant solution?

10. Is the standardization of the NaOH solution described as a titration of an approximate concentration of NaOH solution with an accurately known concentration of KHP solution as the titrant?

11. Does the essay describe the method used to prepare a solution from a pure solid as first weighing the solid, dissolving the solid in an appropriate solvent (such as water), and then diluting the solution in a final volume using a volumetric flask?

12. Are all the necessary data (exact concentration/molarity of NaOH; molar ratio HCl/NaOH of 1:1; exact volume of NaOH/titrant added; and volume of analyte used) required to calculate the concentration of HCl clearly listed?

13. Does the essay describe that the concentration of HCl solution is calculated by: 1. determining the number of moles of NaOH added (concentration of NaOH multiplied by volume of NaOH); 2. then multiplying the moles of NaOH added by the stoichiometric ratio of HCl and NaOH (1:1) to determine number of moles of HCl present; 3. dividing the number of moles of HCl by the final total volume of the HCl solution?

14. Are there any spelling or grammatical errors in the essay? (none, some, many)

15. Are there any incorrect or misleading statements?

16. How would you rate this text? (1-10)

A titration is a form of chemical analysis in which the concentration of an unknown solution, the analyte, is determined by reacting it with a known concentration and volume of another solution, the titrant. The concentration of the titrant is determined through a process called standardization. Once the solution's concentration is known, it is a standard solution. Standard solutions are necessary in titrations because there is otherwise no means to determine the concentration of the analyte. A standard solution is prepared in this case by measuring out a known mass of the NaOH solid on the analytical balance and mixing it with a known volume of water, creating a primary standard solution of NaOH. Alternatively, you could standardize the NaOH through titration with the primary standard solution of KHP. To perform the strong acid-strong base titration, you would place the titrant (NaOH) in a buret and place the analyte (HCl) and indicator (phenolphthalein) in a beaker. Record the volume of HCl in the beaker before adding the phenolphthalein. Invert a test tube over the top of the buret to stop the NaOH from reacting with CO2 in the air. You would then add a known volume of the NaOH to the HCl until the HCl solution changes color. This happens because the indicator phenolphthalein changes color at the equivalence point, where the NaOH has fully reacted with the HCl. Record the volume of NaOH added at the equivalence point so you can calculate the concentration of HCl. At the equivalence point M1V1=M2V2, so to find the concentration of the unknown HCl solution you would multiply the molarity and volume of the NaOH solution titrated at the equivalence point and divide by the volume of HCl originally in the beaker.

Explanation / Answer

(1) Yes, the topic deals with the concept of titration.

(2) Yes, unkown concentraion is called analyte and known concentration as titrant.

(3) Yes

(4) Yes, titrant must be sdandardised solution otherwise calculations will be incorrect.

(5) Yes.

(6) Yes.

(7) Yes, because it reacts with atmospheric CO2.

(8) No, It is not clearly mentioned to which solution (NaOH or HCl) indicator is to be added.

(9) Yes, it mentions that titrant (NaOH) reacts with atmospheric CO2 hence its concentration will decrease.

(10) No, standardization of naOH is not describd as titration.

(11) No.

(12) Yes.

(13) Yes.

(14) Some e.g. burette is written as buret.

(15) 7/10.

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