What is the ratio of concentration of salt to concentration of weak acid in a buffer solution to maintain its $pH$ value at $7.2$ $(pK_{a} = 6.2)$?

Which one of the following is not a 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

Which of the following mixtures in water acts as a basic buffer?

In which of the following combinations is buffer action expected?
$(a)$ $NH_4OH + NH_4Cl$
$(b)$ $HCl + NaCl$
$(c)$ $NH_4OH + HCl$ in $2:1$ mole ratio
Select the correct answer using the code given below.

$A$ solution of $H_3BO_3$ and borax is known as: