According to the Bronsted-Lowry acid-base theory,which ion is responsible for the acidity of an aqueous solution of an acid?

Complete and balance the following chemical equations:
$(a)$ $Ca(OH)_{2} + Cl_{2} \longrightarrow$
$(b)$ $CaSO_{4} \cdot 1/2 H_{2}O + H_{2}O \longrightarrow$
$(c)$ $Na_{2}CO_{3} \cdot 10H_{2}O \xrightarrow{\text{air}} \dots$

$15 \, mL$ of water and $10 \, mL$ of sulphuric acid are to be mixed in a beaker.
$(i)$ State the method that should be followed with reason.
$(ii)$ What is this process called?

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?

Who defined acid and base on the basis of chemical properties?

What is the $pOH$ value of a $10^{-4} \; M$ aqueous solution of $HCl$?