A solution of hydrochloric acid of unknown concentration was titrated with 0.10 M NaOH. If a 100.-mL sample of the HCl solution required exactly 1.0 mL of the NaOH solution to reach the equivalence point, what was the initial pH of the HCl solution? g

The Ph is 3

Explanation:

First of all, calculate the concentration of the acid.

The balanced equation of reaction is:

HCl + NaOH ===> NaCl + H2O

Using titration equation of formula

CAVA/CBVB = NA/NB

Where NA is the number of mole of acid = 1 (from the balanced equation of reaction)

NB is the number of mole of base = 1 (from the balanced equation of reaction)

CA is the concentration of acid = ?

CB is the concentration of base = 0.1M

VA is the volume of acid = 100 mL

VB is the volume of base = 1mL

Substituting

CA×100/0.1×1 = 1/1

Therefore CA =0.1×1×1/100×1

CA = 0.001 M (this is the hydrogen ion concentration)

Ph of the acid is calculated using

Ph = -log [H+]

= -log 0.001

= 3

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.