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 ?
Hydrogen gas is usually liberated when an acid reacts with a metal.
Take few pieces of zinc granules and add $5\,ml$ of dilute $H_2SO_4$. Shake it and pass the gas produced into a soap solution. The bubbles of the soap solution are formed. These soap bubbles contain hydrogen gas.
$2{H_2}S{O_4}\, + \,Zn\, \to Zn{(S{O_4})_2}\, + \,2{H_2} \uparrow $
We can test the evolved hydrogen gas by its burning with a pop sound when a candle is brought near the soap bubbles.
Why does dry $HCl$ gas not change the colour of the dry litmus paper ?
Write word equations and then balanced equations for the reaction taking place when -
$(a)$ dilute sulphuric acid reacts with zinc granules.
$(b)$ dilute hydrochloric acid reacts with magnesium ribbon.
$10 \,mL$ of a solution of $NaOH$ is found to be completely neutralised 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 neutralise it will be ...... $mL$
How is the concentration of hydroxide ions $(OH^-)$ affected when excess base is dissolved in a solution of sodium hydroxide ?
Why does distilled water not conduct electricity, whereas rain water does ?