You have been provided with three test tubes. One of them contains distilled water and the other two contaln an acidic solution and a basic solution, respectlvely. If you are glven only red litmus paper. how will you identify the contents of each test tube ?

Do basic solutions also have $H^+_{(aq)}$ ions ? If yes, then why are these basic ?

Equal lengths of magnesium ribbons are taken in test tubes $A$ and $B$. Hydrochloric acid $(HCl)$ is added to test tube $A$, while acetic acid $(CH_3COOH)$ is added to test tube $B$. Amount and concentration taken for both the acids are same. In which test tube will the fizzing occur more vigorously and why ?

How is the concentration of hydroxide ions $(OH^-)$ affected when excess base is dissolved in a solution of sodium hydroxide ?

Five solutions $A,\,B,\,C,\,D$ and $E$ when tested with universal indicator showed $pH$ as $4,\,1,\,11,\,7$ and $9$, respectively. Which solution is

$(a)$ neutral ?

$(b)$ strongly alkaline ?

$(c)$ strongly acidic ?

$(d)$ weakly acidic ?

$(e)$ weakly alkaline ?

Arrange the $pH$ in increasing order of hydrogen-ion concentration.

What will happen if a solution of sodium hydrocarbonate is heated ? Give the equation of the reaction involved.