Question

after transferring a 10.00 ml sample of the hcl solution into 125 ml erlenmeyer flask, 3 drops of phenolphthalein and about 50 ml of distilled water are added. the resulting solution requires 44.00 ml of 0.1250 m naoh solution to reach the end point. calculate the molarity of hcl solution?

Answer 1

The molarity of the HCl solution can be calculated using the volume and molarity of the NaOH solution needed to reach the equivalence point in a titration. Since the stoichiometry is 1:1, the moles of HCl neutralized are equal to the moles of NaOH used. The molarity of the HCl is then moles of HCl divided by the volume of the HCl solution in liters.

We get 0.550 M HCl.

Step-by-step explanation:

To calculate the molarity of the HCl solution, we must use the information from the titration experiment. The reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is a one-to-one stoichiometry as per the reaction equation:

HCl(aq) + NaOH(aq) → NaCl (aq) + H₂O(l)

Given that 44.00 mL of 0.1250 M NaOH is required to neutralize 10.00 mL of the HCl solution, we can calculate the moles of NaOH used:

(0.1250 mol/L NaOH) × (0.04400 L NaOH) = 0.00550 moles NaOH

Since the stoichiometry of the reaction is 1:1, the moles of HCl neutralized is also 0.00550 moles.

To find the molarity of the HCl solution:

Molarity = moles of solute / liters of solution

We have 10.00 mL of HCl, which is 0.01000 L (since 1 mL = 0.001 L).

Therefore, the molarity of the HCl solution is:

0.00550 moles HCl / 0.01000 L = 0.550 M HCl