$H A$ is a weak acid. At $25^{\circ} C$, the molar conductivity of $0.02\, M\, H A$ is $150\, \Omega^{-1} cm ^{2} mol ^{-1}$. If its $\Lambda_{ m }^{ o }$ is $300\, \Omega^{-1} cm ^{2} mol ^{-1}$, then equilibrium constant of $H A$ dissociation is
Given, molar conductivity \(\left(\Lambda_{m}\right)=300\, \Omega^{-1} cm ^{2} mol ^{-1}\) Limiting molar conductivity \(\left(\Lambda_{m}^{o}\right)=150\, \Omega^{-1} cm ^{2} mol ^{-1}\) Concentration \((C)=0.02\, M\) \(\therefore\) Degree of dissociation \((\alpha)=\frac{\Lambda_{m}}{\Lambda_{m}^{o}}\) \(\alpha=\frac{150}{300} =0.5\) Now, by using following reaction, we can determine the value of its dissociation constant \(K_{a}=\frac{C \alpha^{2}}{(1-\alpha)}\) \(K_{a}=\frac{0.02 \times(0.5)^{2}}{(1-0.5)}\) \(=\frac{0.02 \times 0.5 \times .5}{0.5}=0.01\)
The hydride of fluorine is hydrofluoric acid. Another name for it is an electron-rich hydride. Because HF possesses three lone pairs of electrons, it is electron-rich. These are within the group 17 element (halogen) category of hydride. One hydrogen atom and one fluorine atom are found in each molecule of hydrofluoric acid. When hydrogen fluoride is dissolved in water, hydrofluoric acid is produced. As a result, hydrofluoric acid is an aqueous solution of hydrogen fluoride. Fluoride from hydrogen is a very dangerous substance. If fluids are ingested, they may harm internal organs and can prove fatal if not addressed right once. If this gas is breathed, it may burn the eyes, nose, and throat and irritate those areas.
Hydrogen fluoride is formed by the two following equations:
H2 + F2 → 2HF (dark)
CaF2 + H2SO4 → 2HF + CaSO4
Hydrogen fluoride dissociates in water as follows:
HF (aq) + H2O(l) → H3O+ (aq) + F– (aq)
HF (aq) + H2O(l) ← H3O+ (aq) + F– (aq)
Fluorescent light bulbs, aluminum, plastics, medicines, pesticides, and electrical components are all made with hydrogen fluoride. The production of refrigerants uses 60% of the hydrogen fluoride used in manufacturing.
Using hydrogen fluoride, you can etch metal and glass.
An electrochemical cell is a device that is used to create electrical energy through the chemical reactions which are involved in it. The electrical energy supplied to electrochemical cells is used to smooth the chemical reactions. In the electrochemical cell, the involved devices have the ability to convert the chemical energy to electrical energy or vice-versa.
Classification of Electrochemical Cell:
Cathode
Denoted by a positive sign since electrons are consumed here
A reduction reaction occurs in the cathode of an electrochemical cell
Electrons move into the cathode
Anode
Denoted by a negative sign since electrons are liberated here
An oxidation reaction occurs here
Electrons move out of the anode
Types of Electrochemical Cells:
Galvanic cells (also known as Voltaic cells)
Chemical energy is transformed into electrical energy.
The redox reactions are spontaneous in nature.
The anode is negatively charged and the cathode is positively charged.
The electrons originate from the species that undergo oxidation.
Electrolytic cells
Electrical energy is transformed into chemical energy.
The redox reactions are non-spontaneous.
These cells are positively charged anode and negatively charged cathode.
