Question

How can carbon dioxide be prepared from an acid?

Answer 1

Metal carbonates react with dilute acids to form salt, water and carbon dioxide gas. Thus, carbon dioxide can be prepared by reacting any metal carbonate with any dilute acid.
Example: Carbon dioxide gas is liberated when sodium carbonate reacts with dilute hydrochloric acid.
${\mathrm{Na}}_2{\mathrm{CO}}_3+2\mathrm{HCl}\underset{}{\to 2}\mathrm{NaCl}+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$