Name the sodium compound which is used for softening hard water.
$ Mg(OH)_2 $
$ Ca{(OH)} _{3} $
$Al_{2} O _{3} $
$Na _{2} CO _{3} \cdot 10 H _{2} O$
Plaster of Paris should be stored in a moisture-proof container. Explain why ?
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid ?
Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas ?
Write word equations and then balanced equations for the reaction taking place when -
$(a)$ dilute sulphuric acid reacts with aluminium powder.
$(b)$ dilute hydrochloric acid reacts with iron filings.
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 ?