Chemical effects of electric current

In the making of conductivity detector, how are the two cells connected together?

• In parallel

• In series

• With a switch

• With a rubber band

Why are metals good conductors of electricity?

• They have tightly bound electrons

• They have free-moving electrons

• They have high resistance

• They are solid at room temperature

What color writing would be observed if the negative terminal of the battery is connected to the pencil on a turmeric coated canvas?

• Yellow

• Red

• Pink

• Colourless

In the magical writing experiment, what happens to water molecules when an electric current is passed through the wet canvas?

• They evaporate

• They undergo electrolysis to produce ions

• They solidify

• They become alkaline

If the pencil is connected to the positive terminal of the battery, what is the expected color of the writing on the phenolphthalein-treated paper?

• Pink

• Colourless

• Red

• Yellow

During the electrolysis of NaCl, why does phenolphthalein turn pink near the cathode?

• Chlorine gas is formed at the cathode, making the solution acidic.

• Hydrogen gas is produced, and the solution near the cathode becomes basic.

• NaCl reacts with water, producing chlorine gas and making the solution neutral.

• The reaction produces NaOH, causing the solution near the cathode to become basic.

In electrolysis, which of the following best describes the movement of ions in the electrolyte?

• Cations move toward the anode, and anions move toward the cathode.

• Cations move toward the cathode, and anions move toward the anode.

• Cations and anions both move toward the anode.

• Cations and anions both move toward the cathode.

What is the primary reason for the vigorous bubbling observed near the cathode during the electrolysis of NaCl?

• The formation of chlorine gas.

• The reduction of hydrogen ions to hydrogen gas.

• The oxidation of hydroxide ions.

• The decomposition of NaCl into sodium and chlorine gas.

Why is KI solution used in the experiment, and what does the color change in KI signify?

• The yellow color indicates the formation of iodine due to chlorine gas.

• KI solution helps in conducting electricity; the yellow color indicates a basic solution.

• KI reacts with NaCl, producing a yellow color due to sodium ions.

• KI solution confirms the presence of oxygen gas, turning yellow in its presence.

The electrolysis of NaCl produces chlorine gas at the anode. What would happen if you increase the concentration of NaCl in the solution?

• More chlorine gas is produced at the anode.

• The reaction would slow down as the solution becomes more saturated.

• Hydrogen gas would be produced at both electrodes.

• The phenolphthalein would no longer change color.