Answer to Question #141232 in General Chemistry for Kelly Lozano

Question

the pH of solution of 0.0100 mol dm3 hydrochloric acid is 2.A 10 cm3 sample of acids is measured out and distilled water added to dilute it to a total volume of 100 cm3.how do the hydrogen ion concentration and pH change as the solution is diluted

Answer 1

Calculating the moles of $HCl$ in the solution gives;

$n(HCl_{(aq)})=c(HCl_{(aq)})+V(HCl_{(aq)})$

Where $n(HCl_{(aq)})$ $=$ Moles of $HCl$

$c(HCl_{(aq)})=$ Concentration of $HCl$ in $mol/L$

$V(HCl_{(aq)})=$ Volume of the solution in $L$

Applying the formula;

$n(HCl_{(aq)})=c(HCl_{(aq)})+V(HCl_{(aq)})$

$=$ $100ml\over 1000ml$ $\times 0.100L=0.0100mol$

Diluting the solution increases it's concentration by a factor of 10 hence increasing its acidity.

Dilution of the solution further raises its PH as it increases by a factor of 10 $(1.00+1=2.00)$

In the event, the PH of the solution increases.

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