Which of the following,when added to a solution of acetic acid,will decrease the concentration of hydrogen ions?

$A$ litre of solution is saturated with $AgCl$. To this solution if $1.0 \times 10^{-4} \ mol$ of solid $NaCl$ is added,what will be the $[Ag^{+}]$ compared to the original concentration,assuming no volume change?

When $HCl$ is added to a saturated solution of $NaCl$,pure $NaCl$ precipitates because:

Pure $NaCl$ is prepared by passing $HCl$ gas through a saturated solution of common salt in water. The principle used is:

Among the following,the correct statement is

Consider the nitration of benzene using mixed conc. $H_2SO_4$ and $HNO_3$. If a large amount of $KHSO_4$ is added to the mixture,the rate of nitration will be