What will be the value of $pH$ if blue litmus paper turns red in an aqueous solution?

If $[H_3O^+] = 10^{-6} \ M$ in an aqueous solution,what is the $pH$ of the solution?

$A$ dry pellet of a common base $B$,when kept in open,absorbs moisture and turns sticky. The compound is also a by-product of the chlor-alkali process. Identify $B$. What type of reaction occurs when $B$ is treated with an acidic oxide? Write a balanced chemical equation for one such reaction.

The colour of $pH$ paper strip at the $pH$ values of $1, 7,$ and $14$ will be:

Define alkalies and give an example.

What happens when a solution of an acid is mixed with a solution of a base in a test tube?
$(i)$ The temperature of the solution increases
$(ii)$ The temperature of the solution decreases
$(iii)$ The temperature of the solution remains the same
$(iv)$ Salt formation takes place