Ka, Kb, pKa and pKb as measures of strength

In aqueous solution hydrogen cyanide behaves as a weak acid. (i) Write an equation for the ionization of hydrogen cyanide in water. (ii) Outline two ways in which a solution of 0.050 $\mathrm{mol\,dm^{-3}}$ $\ce{HCN}$ could be distinguished experimentally from…

(i) Outline the way in which ammonia behaves as a Lewis base during the formation of the complex ion $\ce{[Ag(NH3)2]+(aq)}$. (ii) Determine the pH at 298 K of an aqueous ammonia solution of concentration 0.180 $\mathrm{mol\,dm^{-3}}$. Use section 1 of the data…

The table gives data for four bases at 298 K. Base $K_\mathrm{b}$ p$K_\mathrm{b}$ $\ce{N2H4}$ 5.90 $\ce{C2H5NH2}$ $5.6 \times 10^{-4}$ $\ce{C6H5NH2}$ 9.37 $\ce{C5H5N}$ $1.7 \times 10^{-9}$ Which base has the weakest conjugate acid? A. $\ce{N2H4}$ B.…

The student then used the potassium hydroxide solution standardized in 1c to titrate ethanoic acid, $\ce{CH3COOH}$, whose concentration was not known. (i) Neutralizing 25.00 $\mathrm{cm^3}$ of the acid required 40.00 $\mathrm{cm^3}$ of the standardized…

Hexanoic acid, $\ce{CH3(CH2)4COOH}$, is a weak acid. The graph shows how the pH changes during the titration of a 20.0 $\mathrm{cm^3}$ aqueous solution of hexanoic acid with aqueous sodium hydroxide. (i) Deduce an expression for the equilibrium constant, $K$,…

Hypochlorous acid is a weak acid. In water it is in equilibrium with its conjugate base, the hypochlorite ion, $\ce{OCl-}$, which kills microorganisms far less effectively than the acid molecule does. The graph shows what percentage of the dissolved chlorine…

A small volume of $0.050\ \mathrm{mol\,dm^{-3}}$ hydrobromic acid is placed in a beaker fitted with a pH probe. Distilled water is then run into the beaker at a constant rate and the pH is logged continuously; the temperature is held at 298 K. (i) Sketch, on…