Anodising is a process used to improve the appearance and durability of aluminium articles. Which of the following statements best explains the principle behind anodising?
Aluminium is made the anode and oxidised to form a thicker protective oxide layer.
Anodising is an electrolytic process carried out in a dilute acid bath in which the aluminium article is made the anode. When a current is passed, oxygen produced at the anode reacts with the surface aluminium to form a thick, hard and adherent layer of aluminium oxide.
This artificially produced oxide layer is much thicker than the natural one and protects the metal from further corrosion, while also providing a surface that can be dyed for a better appearance. Aluminium is not being coated with zinc, not being made the cathode, and not being dipped in alkali to make it more reactive; the whole point is to make it less reactive by growing a protective oxide.
Hence, the answer is Aluminium is made the anode and oxidised to form a thicker protective oxide layer.
Similar Questions
In electrolytic refining, the pure metal is used as:
During the electrolytic refining of copper, which of the following correctly matches the components and their roles?
Component Role in Refining Process A. Pure Copper i. Anode B. Impure Copper ii. Cathode C. Acidified Copper Sulphate iii. Electrolyte Which of the following statements are correct for electrolytic refining? a. Copper, zinc, and nickel are refined electrolytically. b. In this method, a thin strip of pure metal is used as cathode. c. The insoluble impurities settled at bottom of the anode are known as anode mud.
What happens at the anode during anodising?
Which method is commonly used to extract sodium from its compound?
Which of the following metals is usually extracted from its ore by electrolytic reduction?
Which of the following is a product formed at the cathode during the electrolysis of brine?
Select the option that is true regarding the following two statements labelled Assertion (A) and Reason (R).
Assertion (A): Metals such as sodium and potassium are extracted by electrolysis.
Reason (R): These metals are highly reactive and cannot be obtained by reduction with carbon.
What is used as an anode in the electrolytic refining of nickel?
Important Questions from Electrochemistry
- At $298 \, K$, given the standard electrode potentials: $E^\circ_{Cu^{2+}/Cu} = 0.34 \, V$, $E^\circ_{Zn^{2+}/Zn} = -0.76 \, V$, $E^\circ_{Fe^{2+}/Fe} = -0.44 \, V$, and $E^\circ_{Ag^{+}/Ag} = 0.80 \, V$.
Based on these values, which of the following reactions is NOT expected to occur spontaneously under standard conditions? You are given three metals 'X', 'Y' and 'Z'. Metal 'X' is found to react with an aqueous solution of both YSO 4and ZSO 4whereas metal 'Z' is found to react only with aqueous solution of YSO 4. Based on these observations, select the correct statement from the following.
If the overpotential of an electrolysis process is increased from 0.5 V to 0.6 V, then the ratio of current densities (In \(\frac{\int0.6 }{\int0.5}\)) of the electrolysis will be equal to (given transfer co - efficient = 0.5)
The chemical potential (μ) of a 2 molar Na2SO4 solution is expressed in terms of mean ionic activity co - efficient (γ±) as
The E°(M+/M) of the cell, SHE||MX|M can be obtained from the plot of (E cell is the cell potential and m is the molality of ideal dilute solution of MX)
