The dissociation constants for acetic acid and $HCN$ at $25\,^{\circ}C$ are $1.5 \times 10^{-5}$ and $4.5 \times 10^{-10}$ respectively. The equilibrium constant for the equilibrium $CN^{-} + CH_3COOH \rightleftharpoons HCN + CH_3COO^{-}$ would be

$A$ soft drink was bottled with a partial pressure of $CO_2$ of $3 \ bar$ over the liquid at room temperature. The partial pressure of $CO_2$ over the solution approaches a value of $30 \ bar$ when $44 \ g$ of $CO_2$ is dissolved in $1 \ kg$ of water at room temperature. The approximate $pH$ of the soft drink is............... $\times 10^{-1}$ (First dissociation constant of $H_2CO_3 = 4.0 \times 10^{-7}$; $\log 2 = 0.3$; density of the soft drink $= 1 \ g \ mL^{-1}$)

When $NaCl$ is dissolved in water,the sodium ion is

What will be the change in acidity if
$(i)$ $CuSO_4$ is added in saturated $(NH_4)_2SO_4$ solution
$(ii)$ $SbF_5$ is added in anhydrous $HF$?

If equivalent conductance of $1 \ M$ benzoic acid is $12.8 \ \Omega^{-1} \ cm^2 \ eq^{-1}$ and if the equivalent conductances of benzoate ion and $H^+$ ion at infinite dilution are $42$ and $288.42 \ \Omega^{-1} \ cm^2 \ eq^{-1}$ respectively,then its degree of dissociation is ............ $\%$

$K_a$ for $CH_3COOH$ is $1.9 \times 10^{-5}$. Calculate the $pH$ at the equivalence point in the titration of $0.1 \ M$ $CH_3COOH$ with $0.1 \ M$ $NaOH$.