Chemical Effects of Electric Current - 2
Test your understanding of chemical effects of electric current including electrolysis, electroplating, electrodeposition, and galvanization applications.
Questions
Mohit took a piece of potato and inserted both ends of a copper wire into it. He connected the wire to a battery. Some change happened after some time in the piece. What is that change?
- A coloured spot is formed on the potato on the side of negative terminal.
- A coloured spot is formed on the potato on the side of positive terminal.
- The whole upper surface of the potato becomes coloured.
- The colour of the copper wire changes.
Why is chromium used for electroplating?
(a) It does not corrode.
(b) It is scratch resistant.
(c) It is cheap, easily available and can be electroplated very easily.
- Only (a)
- Both (a) and (b)
- Only (c)
- Both (b) and (c)
Which of the following statements is true for the purification of copper?
- A pure copper rod is connected to the positive terminal of the battery and copper sulphate solution is the electrolyte.
- A pure copper rod is connected to the positive terminal of the battery and distilled water is the electrolyte.
- An impure copper rod is connected to the positive terminal of the battery and salty water is the electrolyte.
- An impure copper rod is connected to the positive terminal of the battery and copper sulphate solution is the electrolyte.
Why is zinc-coated iron used in bridges?
- Zinc gives shiny appearance to iron.
- Zinc increases the strength of the structure.
- Zinc reacts with iron to produce an alloy which is less affected by temperature change, thereby preventing the structure from developing cracks.
- Zinc protects iron from rusting.
Who discovered the evolution of bubbles of hydrogen and oxygen upon passage of electric current through the electrodes immersed in water?
- Robert Hooke
- William Nicholson
- Einstein
- Edwin Aldrin
Why are food storage cans made of electroplated tin instead of being made of iron?
- Tin is less reactive than iron.
- Tin is more reactive than iron.
- Tin reacts with food to prevent spoiling.
- Tin is a non-reactive metal.
On passage of electric current through a liquid, which of the following would not indicate the occurence of a chemical effect?
- Rise in the temperature of solution
- Deposits of metal seen on electrodes
- Changes of colour of solutions
- None of these
Why does a brand new bicycle have shining handlebar and wheel rims?
- Due to electroplating
- Due to shining of metal
- Due to shining atoms
- Due to electrolysis
Which of the following statements is true about passage of electric current through a copper sulphate solution?
- When electric current is passed through the copper sulphate solution, the copper sulphate does not dissociate.
- The free copper gets drawn to the electrode connected to the negative terminal of the battery.
- The free copper gets drawn to the electrode connected to the positive terminal of the battery.
- The mass of copper that gets deposited on one electrode is more than the mass of copper that gets depleted from the other electrode.
A 1 kg carbon rod was connected to the negative terminal of a battery. A 2 kg copper rod was connected to the positive terminal. Both were dipped in an aqueous solution of copper sulphate and a current was passed for 15 minutes. Which of the following cannot be the mass of the carbon rod after this time?
- 1 kg
- 2 kg
- 2.5 kg
- 3 kg
Which of the following would result in dissolution of copper from one electrode and deposition of it on the other?
- Copper plate connected to the positive terminal, carbon rod connected to the negative terminal, and copper sulphate as the solution
- Carbon rod connected to the negative terminal, copper plate connected to the positive terminal, and copper sulphate as the solution
- Carbon rod connected to the negative terminal, copper plate connected to the positive terminal and an aqueous solution of sulphuric acid as the solution
- Carbon rod connected to the postive terminal of the battery, copper plate connected to the negative terminal of the body, and copper sulphate as the solution