Which of the following statements is true for an aqueous solution of $CuSO_4$?

If the $pKa$ of lactic acid is $5$,then the $pH$ of $0.005 \ M$ calcium lactate solution at $25^{\circ} \ C$ is $........ \times 10^{-1}$ (Nearest integer). The structure of lactic acid is given below:

The addition of solid sodium carbonate $(Na_2CO_3)$ to pure water causes:

The $pH$ of a $NaCl$ solution is:

When a salt of a weak acid and a weak base is dissolved in water at $25\,^{\circ}C$,the $pH$ of the resulting solution will always

Which among the following salts turns blue litmus red in its aqueous solution?