HSC Science (Electronics) १२ वीं कक्षा - Maharashtra State Board Important Questions

Which cells is used as a source of power in flashlights?

Write electrode reactions and overall cell reaction when Leclanche's dry cell generates electricity.

Calculate molar conductivity for 0.5 M BaCl₂ if its conductivity at 298K is 0.01 Ω^–1 cm^–1.

Calculate standard Gibbs energy change at 25°C for the cell reaction.

\[\ce{Cd_{(s)} + Sn^{2+}_{ (aq)} -> Cd^{2+}_{ (aq)} + Sn_{(s)}}\]

\[\ce{E^0_{cd}}\] = –0.403 V, \[\ce{E^0_{Sn}}\] = –0.136 V

Draw labelled diagram of H₂ – O₂ fuel cell.

What is the SI unit of molar conductivity?

Write any two difficulties of setting SHE (Standard Hydrogen Electrode).

Write the net cell reaction during discharging of lead accumulator.

Write the names and chemical formulae of any one ore of zinc.

Write the names and chemical formulae of any one ore of iron.

What are Ellingham's diagrams? Write 2 features of it.

The process of leaching alumina, using sodium carbonate is called

• Bayer's process
• Decomposition
• Cyanide process
• Hall's process

What is the chemical composition of malachite?

1. CuO . CuC0₃
2. Cu(OH)₂ CuC0₃
3. CuO.Cu(OH)₂         
4. Cu₂O . Cu(OH)₂

The integrated rate equation for first order reaction is A → products

Explain calcination with reactions.

Sucrose decomposes in acid solution into glucose and fructose according to the first order rate law with t_1/2 = 3 hours. What fraction of the sample of sucrose remains after 8 hours?

Write the reactions involved in the zone of reduction in blast furnace during extraction of iron.

The rate constant for a first order reaction is 100 s^–1. The time required for completion of 50% of reaction is _______.

(A) 0.0693 milliseconds

(B) 0.693 milliseconds

(C) 6.93 milliseconds

(D) 69.3 milliseconds

Silica is added to roasted copper ore during smelting process to remove _______.

(A) ferrous sulphide

(B) ferrous oxide

(C) cuprous sulphide

(D) cuprous oxide

Define Hydrometallurgy?