What is the $pH$ of $10^{-1} \, M$ formic acid?

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 $3.7 \%$ dissociated. The value of the dissociation constant,$K_a,$ for this acid will be:

For a $10^{-3} \ M \ H_2CO_3$ solution,if the degree of dissociation $\alpha = 10\%$,what will be the value of $pH$?

Which of the following formulae is used to find the $[OH^{-}]$ ion concentration of a weak monoacidic base?

For a $10^{-3} \ M \ HCN$ solution,if the degree of dissociation $\alpha = 10\%$,find the $K_a$ and $pH$ of the solution.

The $pK_a$ of a weak acid is $5.85$. The concentrations of the acid and its conjugate base are equal at a $pH$ of (in $.85$)