Calculate the molar ratio of a weak acid $HA$ $(K_a=10^{-6})$ and its salt with a strong base,so that the $pH$ of the buffer solution is $6$.

The buffer system which helps to maintain the $pH$ of blood between $7.26$ to $7.42$ is:

Buffer solution is prepared by mixing

What is the $pH$ of a solution containing $50 \ mL$ each of $0.1 \ M$ sodium acetate and $0.01 \ M$ acetic acid (in $.5$)? $(pK_{a} \ CH_3COOH = 4.50)$

Find $pH$ of the resultant solution formed by the addition of $500 \ mL$ $0.1 \ M$ $Ba(OH)_2$ and $500 \ mL$ $0.6 \ M$ $NH_4Cl$ in $1 \ L$ pure $H_2O$ at $25 \ ^oC$ (Use $log \ 2 = 0.3$,$log \ 3 = 0.5$,$log \ 5 = 0.7$,$K_b(NH_3) = 10^{-5}$)

Calculate the $pH$ of a buffer solution containing $0.01 \ M$ salt and $0.004 \ M$ weak acid. $(pK_{a} = 4.762)$