Science Please Help ASAP 1. (TCO 4) A chemist found a bottle of an unknown conce

Question

Science Please Help ASAP

  1. (TCO 4) A chemist found a bottle of an unknown concentration of HCl solution sitting on the shelf in the lab. She found that the pH was 2.0.

(a) Is the solution an acid or a base? How do you know? (10 points)
(b) What is the concentration of H3O+ ions in the solution? (5 points)
(c) The chemist decided to titrate the unknown solution with NaOH to determine its concentration. She placed a 25.0 mL sample of the solution into a flask and mixed in a few drops of phenolphthalein. She then slowly added NaOH and found that 18.3 mL of 2.5 M NaOH was needed to neutralize the HCl. What is the concentration of HCl in the unknown solution? (10 points) (Points : 25)     

Explanation / Answer

1) acid

2) p^H =-log[H^+]

2=-log[H^+]

[H^+]= 10^-2M

3) M1V1=M2V2

18.3*2.5=M2*25

M2= 1.8 M

the concentrtaion of unknown sample of HCl is 1.8M

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