Equal volumes of three acid solutions of $\mathrm{pH} 3,4$ and 5 are mixed in a vessel. What will be the…
Equal volumes of three acid solutions of $\mathrm{pH} 3,4$ and 5 are mixed in a vessel. What will be the $\mathrm{H}^{+}$ion concentration in the mixture?
$1.11 \times 10^{-3} \mathrm{M}$
$1.11 \times 10^{-4} \mathrm{M}$
$3.7 \times 10^{-4} \mathrm{M}$
$3.7 \times 10^{-3} \mathrm{M}$
Solution
$\mathrm{N}_1 \mathrm{~V}_1+\mathrm{N}_2 \mathrm{~V}_2+\mathrm{N}_3 \mathrm{~V}_3=\mathrm{N}_{\mathrm{m}} \mathrm{V}_{\mathrm{m}}$
or $10^{-3} \times 1+10^{-4} \times 1+10^{-5} \times 1=\mathrm{N}_{\mathrm{m}} \times 3$
or $1.11 \times 10^{-3}=\mathrm{N}_{\mathrm{m}} \times 3$
or $\mathrm{N}_{\mathrm{m}}=0.37 \times 10^{-3}$
$\left[\mathrm{H}^{+}\right]=3.7 \times 10^{-4} \mathrm{M}$