How carbon dioxide prepared in lab?

Explanation:

In laboratory, carbon dioxide is not obtained from the air, carbon dioxide is prepared from carbonates by adding acids to the carbonates. In this experiment carbon dioxide is prepared by the reaction of marble with hydrochloric acid.

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.