$A$ buffer solution of $100 \ mL$ has a $pH$ value of $4$. When $1 \ mL$ of dilute $HCl$ is added to it,what happens to the $pH$ of the buffer solution?

The $pH$ of a buffer solution containing $25 \ mL$ of $1 \ M \ CH_3COONa$ and $25 \ mL$ of $1 \ M \ CH_3COOH$ will be appreciably affected by $5 \ mL$ of

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 $\log \ 2 = 0.3$,$\log \ 3 = 0.5$,$\log \ 5 = 0.7$,$K_b(NH_3) = 10^{-5}$)

Which of the following solutions does not act as a buffer $:-$

The ionization constant $(K_a)$ of a certain weak acid is $10^{-4}$. What should be the $[salt]$ to $[acid]$ ratio if we have to prepare a buffer with $pH = 5$ using this acid and one of its salts?

In a mixture of acetic acid and sodium acetate,the ratio of the concentration of the salt to the acid is increased ten times. Then the $pH$ of the solution: