How does the acidity of an acidic aqueous solution change as the concentration of $[H_{3}O^{+}]$ decreases?

Which ions are produced when caustic soda undergoes ionization in water?

According to the Bronsted-Lowry acid-base theory,the substance which donates a proton $(H^+)$ to another substance is called ............

Write true or false for the following statement:
On the $pH$ scale,we can measure $pH$ from $0$ (very acidic) to $14$ (very alkaline).

Tooth enamel is the hardest substance in our body. Name the compound of which it is made up. At what $pH$ of the mouth does it get corroded? State the role of bacteria present in the mouth. Suggest a method to prevent tooth decay.

Write true or false for the following statement:
Higher is the hydronium ion concentration,higher is the $pH$ value.