Ionic product of water, Kw

Which solution has a pH of 11.0 at 298 K? A. $10^{-3}\ \mathrm{mol\,dm^{-3}}$ $\ce{KOH(aq)}$ B. $10^{-11}\ \mathrm{mol\,dm^{-3}}$ $\ce{KOH(aq)}$ C. $10^{-3}\ \mathrm{mol\,dm^{-3}}$ $\ce{NH3(aq)}$ D. $10^{-3}\ \mathrm{mol\,dm^{-3}}$ $\ce{HCl(aq)}$

Which of these solutions has a pH greater than 7 at 25 °C? A. $[\ce{H+}] = 1.0 \times 10^{-5}\ \mathrm{mol\,dm^{-3}}$ B. $[\ce{OH-}] = 1.0 \times 10^{-10}\ \mathrm{mol\,dm^{-3}}$ C. $[\ce{H3O+}] = 1.0 \times 10^{-11}\ \mathrm{mol\,dm^{-3}}$ D.…

A solution has a pH of 4.0 at 298 K. What is the hydroxide ion concentration, [$\ce{OH-}$], in $\mathrm{mol\,dm^{-3}}$? A. 10 B. $10^{-4}$ C. $10^{-10}$ D. $10^{-18}$

An aqueous solution at 298 K has a pH of 9.20. $K_\mathrm{w} = [\ce{H+}][\ce{OH-}] = 1.00 \times 10^{-14}$ at 298 K What is the hydroxide ion concentration of the solution, in $\mathrm{mol\,dm^{-3}}$? A. $6.31 \times 10^{-10}$ B. $1.58 \times 10^{-9}$ C.…