Name the sodium compound which is used for softening hard water.
$ Mg(OH)_2 $
$ Ca{(OH)} _{3} $
$Al_{2} O _{3} $
$Na _{2} CO _{3} \cdot 10 H _{2} O$
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 ?
Why does distilled water not conduct electricity, whereas rain water does ?
Name the substance which on treatment with chlorine yields bleaching powder.
Write an equation to show the reaction between Plaster of Paris and water.
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 ?