The nails are fitted in a cork and are kept in a 100 ml beaker. Then these are connected to the two terminals of a 6 volt battery along with a bulb and a switch. Now some dilute HCl is poured in the beaker and current is allowed to pass through the circuit. The same experiment is carried out using glucose and alcohol solutions separately in place of HCl.
Observations
The bulb glows in HCl solution only. The reason is that HCl solution dissociates into H+ and Cl– ions which help to conduct electricity while glucose and alcohol solutions do not dissociate into ions and so, do not conduct electricity. That is why we find the bulb glowing in HCl solution only.
Conclusions
The above activity proves that all acids contain hydrogen but not all compounds containing hydrogen are acids. Due to this reason compounds such as alcohols and glucose although contain hydrogen, but they are not categorized as acids.
