6.
State the meaning of the terms:
(a) Electro-magnetic induction (b) Electrolysis
(c) Electrodes
(d) Electrorefining of metals
Answers
Answer:
electromagnetic induction:
Electromagnetic Induction or Induction is a process in which a conductor is put in a particular position and magnetic field keeps varying or magnetic field is stationary and a conductor is moving. This produces a Voltage or EMF (Electromotive Force) across the electrical conductor.
electrolysis:
In chemistry and manufacturing, electrolysis is a technique that uses direct electric current to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell.
electrode:
An electrode is a conductor that is used to make contact with a nonmetallic part of a circuit. Electrodes are commonly used in electrochemical cells (see Figure 1), semiconductors like diodes, and in medical devices.
Electrorefining of metals:
Electrorefining is a process in which materials, usually metals, are purified by means of an electrolytic cell. ... An electric current is passed between a sample of the impure metal and a cathode when both are immersed in a solution containing cations of the metal.
Answer:
a) Electromagnetic Induction is a current produced because of voltage production (electromotive force) due to a changing magnetic field.
This either happens when a conductor is placed in a moving magnetic field (when using AC power source) or when a conductor is constantly moving in a stationary magnetic field.
Michael Faraday arranged a conducting wire as per the setup given below, attached to a device to measure the voltage across the circuit. When a bar magnet was moved through the coiling, the voltage detector measures the voltage in the circuit.
b) Electrolysis is defined as a process of decomposing ionic compounds into their elements by passing a direct electric current through the compound in a fluid form. The cations are reduced at cathode and anions are oxidized at the anode.
For example, acidified or salt-containing water can be decomposed by passing electric current to their original elements hydrogen and oxygen. Molten sodium chloride can be decomposed to sodium and chlorine atoms.
c) it is any substance that is a good conductor of electricity and these substances usually connect non-metallic parts of a circuit for example semiconductors, an electrolyte, plasmas, vacuum or even air. The term was first coined by William Whewell and derived from Greek words Elektron, which means “amber” and hodos which translates to “a way.”
An early version of an electrode was the electrophore which was used to study static electricity. It was invented by Johan Wilcke. To help you understand the concept in simple terms, an electrode is a point where the current enters and leaves the electrolyte. Notably, an electrode does not necessarily have to metals.
When studying electrodes, there are a few things that we come across. The two common terms we hear is cathode and anode. The cathode is the current that leaves the electrodes or cathode is a result of reduction reaction taking place in an electrolyte mixture. Here electrons are released from the electrode and the surrounding solution is reduced.
d) The below-given table outlines the methods used to refine five metals. It is necessary to choose the electrolyte and other conditions so that both anodic dissolution and metal deposition proceed with high efficiency while none of the impurity metals can move from the anode to the cathode. Clearly, there must be no passivation of the anode and the aim is to produce a deposit at the cathode of good quality, sometimes extremely crystalline. Additives are applied to the electrolyte when necessary to impose the right behaviour on both electrodes.
Explanation: