Calculate the ${H^ + }$ ion concentration in a $1.00\,(M)$ $\,HCN\,$ litre solution $({K_a} = 4 \times {10^{ - 10}})$

At  $25\,^o C$, the dissociation constant of a base $BOH$ is $1.0 \times {10^{ - 12}}$. The concentration of Hydroxyl ions in $0.01\, M$ aqueous solution of the base would be

${K_b}$ of $N{H_4}OH = 1.8 \times {10^{ - 5}}$ calculate $pH$ of $0.15$ $mol$ $N{H_4}OH$ and $0.25$ $mol$ $N{H_4}OH$ containing solution.

The first ionization constant of $H _{2} S$ is $9.1 \times 10^{-8}$. Calculate the concentration of $HS ^{-}$ ion in its $0.1 \,M$ solution. How will this concentration be affected if the solution is $0.1\, M$ in $HCl$ also? If the second dissociation constant of $H _{2} S$ is $1.2 \times 10^{-13}$, calculate the concentration of $S^{2-}$ under both conditions.

Write characteristic and uses of weak base equilibrium constant ${K_b}$.

Accumulation of lactic acid $(HC_3H_5O_3),$ a monobasic acid in tissues leads to pain and a feeling of fatigue. In a $0.10\, M$ aqueous solution, lactic acid is $3.7\%$ dissociates. The value of dissociation constant, $K_a,$ for this acid will be