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The flask contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.140 M NaOH . It requires 24.7 mL of the NaOH solution to reach the end point of the titration. A buret filled with a titrant is held above a graduated cylinder containing an analyte solution. What is the initial concentration of HCl

Answer :

dsdrajlin

Answer:

0.346 M

Explanation:

Let's consider the following neutralization reaction.

NaOH + HCl → NaCl + H₂O

24.7 mL of 0.140 M NaOH react. The reacting moles are:

24.7 × 10⁻³ L × 0.140 mol/L = 3.46 × 10⁻³ mol

The molar ratio of NaOH to HCl is 1:1. The moles of HCl that reacted are 3.46 × 10⁻³ moles.

3.46 × 10⁻³ moles of HCl are contained in 10.0 mL. The molarity of HCl is:

3.46 × 10⁻³ mol/ 10.0 × 10⁻³ L = 0.346 M

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