Advertisements
Advertisements
प्रश्न
Write chemical equation for the event.
Electrolysis of alumina is done.
Advertisements
उत्तर १
The electrolysis of alumina is carried out in a steel tank lined inside with graphite. The graphite lining serves as cathode. Anode is also made up of graphite rods hanging in the molten mass. The electrolyte consists of alumina dissolved in fused Cryolite(Na3AlF6) and Fluorspar(CaF2). Cryolite lowers the melting point of alumina and fluorspar increases the fluidity of the mass so that the liberated aluminum metal may sink at the bottom of the cell. When electric current is passed through this mixture, the aluminum is collected at the cathode in molten state and sinks at the bottom.
Ionization of Alumina:2Al2O3 → 6O-2 + 4Al+3
Reaction at Cathode: 4Al+3 + 12e- → 4Al
Reaction at Anode: 6O-2 → 3O2 + 12e-, C + O2 → CO2
उत्तर २
When electrolysis of alumina is done, aluminium is formed at the cathode and oxygen gas liberated at the anode.
Cathode:
\[\ce{Al^{3+} + 3e^- -> Al_{(l)}}\] (Reduction)
Anode:
\[\ce{2O^2- -> O_{2(g)} + 4e^-}\] (Oxidation)
संबंधित प्रश्न
What do you observe when a few pieces of iron are dropped in a blue solution of copper sulphate?
Fill in the blank
When a piece of copper is added to silver nitrate solution, it turns ............in colour.
How will you obtain Silver chloride from silver nitrate.
Also give balanced equations for the reactions
What do you observe when Magnesium ribbon is burnt in oxygen.
What is meant by the metal reactivity series ? State its importance, (any two points).
Write chemical equation for the event.
Iron filings are dropped in aqueous solution of copper sulphate.
Give a balanced equation for the reversible catalytic reaction involving nitrogen as one of the reactants.
Select the correct answer for the statement given below:
The catalyst used in the catalytic reaction involving the reactants nitrogen and hydrogen.
Complete the statement by filling in the blank with the correct word:
The metal which reacts with steam and the reaction is reversible is ________.
Explain the following reaction with the balanced equation.
Magnesium reacts with dil HCl
Observe the following diagram and identify the type of reaction and write observation.
Which among the following statements is incorrect for magnesium metal?
A metal A, which is used in thermite process, when heated with oxygen gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with HCl and NaOH.
An element A reacts with water to form a compound B which is used in white washing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify A, B and C and give the reactions involved.
A solution of CuSO4 was kept in an iron pot. After few days the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.
Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores.
Explain the following
- Reactivity of Al decreases if it is dipped in HNO3
- Carbon cannot reduce the oxides of Na or Mg
- NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as well as in molten state
- Iron articles are galvanised.
- Metals like Na, K, Ca and Mg are never found in their free state in nature.
