Write the chemical names of two salts belonging to the sodium family.

What is meant by $p$ and $H$ in $pH$?

In a basic aqueous solution,how does the basicity of the solution change as the concentration of $[OH^{-}]$ ions decreases?

Which of the following statements is correct about an aqueous solution of an acid and of a base?
$(i)$ Higher the $pH$,stronger the acid
$(ii)$ Higher the $pH$,weaker the acid
$(iii)$ Lower the $pH$,stronger the base
$(iv)$ Lower the $pH$,weaker the base

$(a)$ What is a universal indicator?
$(b)$ Write the chemical equation involved in the preparation of sodium hydroxide. Name the process.

The physiological reactions occurring in the human body take place in the range of $......\,pH.$