Which one of the following types of medicines is used for treating indigestion?

$10 \,mL$ of a solution of $NaOH$ is found to be completely neutralized by $8 \,mL$ of a given solution of $HCl$. If we take $20 \,mL$ of the same solution of $NaOH$,the amount of $HCl$ solution (the same solution as before) required to neutralize it will be ...... $mL$.

What effect does the concentration of $H^+_{(aq)}$ ions have on the nature of the solution?

Write word equations and then balanced chemical equations for the reactions taking place when:
$(a)$ Dilute sulphuric acid reacts with aluminium powder.
$(b)$ Dilute hydrochloric acid reacts with iron filings.

Why does an aqueous solution of an acid conduct electricity?

Fresh milk has a $pH$ of $6$. How do you think the $pH$ will change as it turns into curd? Explain your answer.