Question

An apparatus was set-up as shown in the figure. It was observed that when an aqueous solution of HCl was taken in the beaker and the circuit was closed, the bulb in the circuit began to glow, but it did not glow when the experiment was repeated with glucose solution. What could be the reason? 

Would the bulb glow if the same experiment is repeated with an aqueous solution of 

(i) NaOH (ii) NaCl? Why?

Answer 1

The bulb could glow when an aqueous solution of HCl was taken because HCl (aq) provided hydrogen and chloride (H⁺ and Cl^–) ions which are carriers of electric charges in a solution, while glucose (being a covalent compound) did not furnish any ions in the solution. 

(i) NaOH: The bulb will glow 

(ii) NaCl: The bulb will glow Because both of them being ionic compounds furnish ions in aqueous solutions.