$A$ solution turns red litmus blue,its $pH$ is likely to be

Do basic solutions also have $H^+_{(aq)}$ ions? If yes,then why are these basic?

$A$ milkman adds a very small amount of baking soda to fresh milk.
$(a)$ Why does he shift the $pH$ of the fresh milk from $6$ to slightly alkaline?
$(b)$ Why does this milk take a long time to set as curd?

Under what soil condition do you think a farmer would treat the soil of his fields with quick lime $(CaO)$,slaked lime $(Ca(OH)_2)$,or chalk $(CaCO_3)$?

Why does an aqueous solution of an acid conduct electricity?

Name the sodium compound which is used for softening hard water.