Sagot :
Answer:
-6.15
Explanations
The formula for calculating the pH of a buffer is expressed as
[tex]pH=pka+log\frac{[salt]}{[acid]}^[/tex]pka of the hydrochloric acid = -6.3
Calclate the moles of the HCl and sodium acetate
[tex]\begin{gathered} moles=molarity\times volume \\ moles\text{ of HCl=0.676M}\times0.275 \\ moles\text{ of HCl=0.1859moles} \end{gathered}[/tex]Calculate the moles of sodium acetate (salt)
[tex]\begin{gathered} moles\text{ of sodium acetate=0.525M}\times0.500 \\ moles\text{ of sodium acetate=0.2625moles} \end{gathered}[/tex]Substitute the given parameters into the formula
[tex]\begin{gathered} pH=pka+log\frac{[0.2625\text{/v}]}{[0.1859\text{/v}]} \\ pH=-6.3+log1.4121 \\ pH=-6.3+0.1498 \\ pH=-6.1502 \end{gathered}[/tex]Hence the pH of this buffer is approximately -6.15