How is the concentration of hydroxide ions $(OH^-)$ affected when excess base is dissolved in a solution of sodium hydroxide?

What are solutions that conduct electricity called?

Give reasons for the following:
$(a)$ Dry $HCl$ gas does not change the colour of dry litmus paper.

$(a)$ Why should curd and sour substances not be kept in brass and copper vessels?

Write true or false for the following statements:
Care must be taken while mixing concentrated nitric acid or sulphuric acid with water. The water must always be added slowly to the acid with constant stirring.

In an attempt to demonstrate electrical conductivity through an electrolyte,the following apparatus was set up. Which among the following statement$(s)$ is(are) correct?
$(i)$ Bulb will not glow because electrolyte is not acidic.
$(ii)$ Bulb will glow because $NaOH$ is a strong base and furnishes ions for conduction.
$(iii)$ Bulb will not glow because circuit is incomplete.
$(iv)$ Bulb will not glow because it depends upon the type of electrolytic solution.
Solution: The apparatus shows a beaker containing a dilute $NaOH$ solution with two nails fixed on a rubber cork. $NaOH$ is a strong base that dissociates completely in water to provide $Na^+$ and $OH^-$ ions. These free ions act as charge carriers,allowing the electric current to flow through the solution and complete the circuit. Therefore,the bulb will glow. Statement $(ii)$ is correct.