In $H_{3}O^{+}$,there is a coordinate covalent bond between $......$ and $......$.

Which of the following is a strong acid?

Equal lengths of magnesium ribbon are taken in two test tubes $A$ and $B$. $H_{2}SO_{4}$ is added to test tube $A$ and $H_{2}CO_{3}$ is added to test tube $B$ in equal amounts.
$(a)$ Write chemical equations for both the reactions.
$(b)$ Out of the two acids taken above,which one will have a lower $pH$ value and lower $H^{+}$ concentration,respectively?

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

Write true or false for the following statement:
The separation of $H^+$ ions from $HCl$ molecules can occur in the absence of water.

What is the effect of an acid on litmus paper?