Metallic and electrolytic conduction - class-XII

Insulators donot conduct electricity due to the absence of ions or electrons.

Insulators are materials that prevent the flow of electric current because they have very few free electrons or ions to carry charge. Conductors, by contrast, allow electricity to pass through them easily.

Mixing 100 ml of 0.1M KCN and 100 ml of 0.1M HCl results in a total volume of 200 ml containing 0.01 moles of HCN and neutralized chloride ions. The concentration of HCN is 0.01 mol / 0.2 L = 0.05 M. Since HCN is a weak acid, [H+] = sqrt(Ka * C) = sqrt(5 * 10^-6 * 0.05) = sqrt(2.5 * 10^-7) = 5 * 10^-4 M.

An electric current causes a magnetic field around it just like a magnet causes a magnetic field. When you moved the compass near an electric field, the magnetic field produced due to the electric field deflects the compass.

Solid NaCl consists of ions held together in a rigid crystal lattice; because these ions are not free to move, the solid cannot conduct electricity. Molten and aqueous forms allow ions to move freely, enabling conduction.

This is a complex stoichiometry and electrolysis problem. After Cu+ is deposited, the electrolysis of water occurs (2H2O -> 2H2 + O2). Calculating moles of electrons from current and time, then applying Faraday's laws, leads to the volumes of H2 and O2 evolved.

Distilled water is a bad conductor of electricity. It do not contains any impurities to carry the current. So the circuit will not be completed for the bulb to glow.

KOH being a strong base is a good conductor of electricity. 

The presence of ionic solute in a solution can be determined by measuring its conductivity because ions are good conductor of electricity.

Copper pyrites (CuFeS2) contain iron and copper sulfides. The initial step in extracting copper from copper pyrites is roasting the ore in the presence of oxygen to remove excess sulfur as sulfur dioxide and convert iron sulfide into iron oxide.

Conductivity (kappa) is defined as the conductance of a solution contained between two electrodes of unit area and unit distance apart. Adding water (dilution) decreases the number of ions per unit volume, thus decreasing the conductivity.

In electroplating, the object to be plated is the cathode. While the cathode gains weight, the anode only loses weight if it is made of the metal being plated (sacrificial anode). Option A is the most general correct statement regarding the setup.

With increase of temperature the ionic mobility increases.

Electrical conductivity $\times $ no. / moles of ions present after dissociation.

Higher the number of ions in solution, higher would be the conductivity of the solution as the number of charge carriers would increase. Hence, higher the degree of ionization greater would be the number of ions in solution.

The electrolyte present in sports drink is sodium chloride.

Conductivity of an aqueous solution depends on degree of ionization of solute. More is the degree of ionization more will be conductivity. Second, important factor on which conductivity depend is temperature.

In photoelectric cells, light energy is converted into electrical energy .Thus $Se$ is used in photocells because of its behaviour to become a conductor in presence of light.

For pure water ${ K } _{ a }=1.8\times { 10 }^{ -16 }$ at $25℃$

For metals the thermal conductivity is mainly a function of the motion of free electrons.As the temperature increases the molecular vibrations increases so they obstruct the free flow of electrons thus reducing conductivity.

Solution:- (B) $63 ; g$

Solution:- (B) $50$

Conductivity in solutions depends on the degree of dissociation. Sulfuric acid (H2SO4) is a strong acid and dissociates completely into ions, whereas boric and phosphorous acids are weak acids and dissociate poorly.

In metallic conductor the current is conducted by flow of free electrons.Ions contain the free electron therefore they conducts the electricity.

The reaction is Al^3+ + 3e- -> Al. 1 mole of Al (27g) requires 3 Faradays (3 * 96500 C). For 40.5g, the moles of Al = 40.5 / 27 = 1.5 moles. Charge = 1.5 * 3 * 96500 = 4.5 * 96500 = 434250 C, which is 4.34 * 10^5 C.

Given,

Conductivity k = (1 / R) * (l / A). Resistance R = 50 ohm, distance l = 0.02 m = 2 cm, area A = 0.0004 m^2 = 4 cm^2. Thus k = (1 / 50) * (2 / 4) = 0.02 * 0.5 = 0.01 S cm^-1.

Specific conductance (kappa) decreases with dilution because the number of ions per unit volume decreases. Conductance and equivalent conductance increase with dilution because the total number of ions or the mobility of ions increases.

Water has very low ionisation constant so it dissociates very low and pure water is consists almost entirely of molecules.

Ionic compounds like potassium chloride (KCl) conduct electricity in the molten state because the crystal lattice breaks down, allowing the K+ and Cl- ions to move freely.

Only CuS solid conducts electricity. NaCl and KCl are electrolytic conductor and diamond is non-conductor.

Water has very low ionisation constant so it dissociates very low and pure water  consists almost entirely of molecules; as no of ions are very less in pure water so normally it will not conduct electricity.

All of the following modifications are necessary to determine the resistance of solution by the usual method of measurements on Wheatstone's bridge principle.

Nickel is a metal and it conducts electricity through its valence shell electrons while nickel sulphate solution conducts electricity through its ions (formed by dissociation of nickel sulphate solutions).

Solution which contains free ions conducts electricity.

A solution of sodium in liquid ammonia at $-33^oC$ conducts electricity. On cooling, the conductivity of this solution ...... The conductivity of the solution is due to presence of ammoniated electrons. With decrease in the temperature, the mobility of ammoniated electrons decreases due to which the electrical conductivity decreases.

Aluminium is metal so its wire will act as metallic conductor and it conducts electricity due to valence shell electrons.

Electrolytic conduction is a chemical change. It involves a redox reaction.
In electrolytic conduction, positive as well as negative ions conduct electricity.
For example, during electrolysis of molten NaCl, both $Na^+$ and $Cl^-$ ions are involved in the conduction of electricity.
Thus, A is false but B is true.

The current-carrying ions in an electrolytic cell are not necessarily discharged at the electrodes. This is true for the electrolysis of aqueous salt solutions in which water is involved in the electrode reactions and not the current carrying ions.
$2H _2O \rightarrow O _2 + 4H^+ +4e^-$    oxidation
$2H _2O + 2e^- \rightarrow H _2 +2OH^-$   reduction

The conductivity of an electrolyte depends on the temperature. With an increase in temperature, the conductivity of an electrolyte increases.This is due to increase in ionic mobility. 

Ammonium acetate is a salt. Salts conduct electricity due to complete dissociation. Ammonium hydroxide is a weak base and does not conduct electricity. Sodium hydroxide is a strong base and conducts electricity. Formic acid is a weak acid and does not conduct electricity. 

$HCl$ is a strong acid and it has ions to carry the current. So the circuit will be completed and the bulb will glow brightly.

Ammonium hydroxide and acetic acid are weak bases and acid respectively. Hence, they are poor conductors. 

The electrical conductivity of a conductor will decrease with an increase in temperature. But for acids bases and salts raising the temperature gives more energy to the ions making them move faster, and hence increasing the conductivity.

Sodium, potassium and Graphite all three are electrical conductor except Diamond which is an insulator of electric current.

Well water conducts electricity due to the presence of ions.

No. of ions in 11 molecule of $Na _2SO _4=3$ 

Water has some impurities in it. So the impurities will carry the current and the bulb will glow.

Ammonium hydroxide is a weak base so it has less ions to carry the current. So the circuit will be completed and the bulb will glow dimly.

Electrical conductivity in an electrolytic solution is directly proportional to the concentration and mobility of the ions present in the solution.

Conduction of electricity takes place due to the presence of free ions.

Electrolytic conduction occurs when a voltage is applied across the electrodes dipped in the electrolytic solution. The ions present in the electrolyte moves. The cations move towards the cathode. In the cathode the cations undergo reduction. The anions move towards the anode. In the anode the anions undergo oxidation. Thus electrolytic conduction accompanies a chemical change.
But no such chemical change occurs in case of metallic conduction.

Option A is the correct answer.

In electrolytic conduction, a voltage is applied across the electrodes dipped into the electrolytic solution. There are ions present in electrolytic solution. Because of the voltage applied, electric current will flow in the solution. The ions will move in the solution. The cations will move towards the cathode, whereas the anions will move towards the anode.
Thus in electrolytic conduction mass is transferred in the form of ions.
Whereas, no such transfer of mass occur in metallic conduction. It is just the flow of electrons. 

In an electrolytic solution when a voltage is applied across the electrodes dipped into the solution, the ions present in the electrolyte move. The cations move towards the cathode, whereas the anions move towards the anode and thus electric current flows through the electrolytic solution. Thus electrolytic conduction occurs because of the flow of ions.

Hydrochloric acid acid is a ionic compound which can easily dissociates into $H^+$ and $Cl^-$ ionsand gives high conductivity.

Metal atoms have outer electrons which are not tied to any other atom. Thus metals have free electrons. This electron can move freely in the metal structure. Because of the presence of this free electron metals can conduct electricity. Electricity is the flow of electrons.

In a conduction process,change of mass was observed. The conduction type can be electrolytic as electrolytic conduction takes place due to flow of ions thus electrolytic conduction involves transfer of matter.

Electrolytic conduction occurs because of the flow of ions. As the temperature increases, the degree of ionization of the electrolyte also increases. Hence the flow of ions also increases. So, electrolytic conduction increases with the increase in temperature.
Metallic conduction occurs because of the flow of electrons. As the temperature rises the metal atoms vibrate more. And hence the resistance offered by the moving electrons also increases. Because of this resistance, the conduction decreases. So metallic conduction decreases with increase in temperature.

Standard KCl solutions (like 0.1M or 0.01M) are used for cell constant determination because their conductivity is accurately known. Saturated KCl is not used because its concentration and conductivity can be unstable or difficult to reproduce precisely.

The substances which allow the flow of electric current are called conductors. The good metal conductors are copper, silver, tin, etc. 

As temperature rises, thermal conductivity of metals decreases due to increase in molecular collisions.

Equivalent conductance can be defined as the conductance produce by an equivalent of ion present in the solution.

For all the solution $Q=i\times t$ is same,

Metallic or electronic conductivity is due to the presence of free electrons or/and holes (positive charge). It depends upon:
(i) Number of valence electrons present in the metal 
(ii) Structure and nature (characteristic) of metal 
(iii) Density of metal 
(iv) Temperature 

${ \Lambda  } _{ eq }^{ \infty  }\left( { Ba }^{ 2+ } \right) =127{ \Omega  }^{ -1 }{ cm }^{ -1 }{ eq }^{ -1 }\ { \Lambda  } _{ eq }^{ \infty  }\left( { Cl }^{ - } \right) =76{ \Omega  }^{ -1 }{ cm }^{ -1 }{ eq }^{ -1 }\ { \Lambda  } _{ eq }^{ \infty  }\left( { Ba }{ Cl } _{ 2 } \right) ={ \Lambda  } _{ eq }^{ \infty  }\left( { Ba }^{ 2+ } \right) +2{ \Lambda  } _{ eq }^{ \infty  }\left( { Cl }^{ - } \right) \ \qquad \qquad \quad =127+76\times 2\ \qquad \qquad \quad =279{ \Omega  }^{ -1 }{ cm }^{ -1 }{ eq }^{ -1 }$

At substantially lower concentrations as concentration increases , conductivity increases. Micelle formation can occur at above critical micelle concentration which is at 25$^0$C for sodium lauryl sulphate. It doesnt form a positively charged colloid .

To maintain neutrality, the total charge on cation is equal to the total charge on anion.

$\Lambda ^{ 0 } _{ m\left( C _{ 6 }H _{ 5 }COOH \right)  }={ \Lambda  } _{ (C _{ 6 }{ H } _{ 5 }CO{ O }^{ - }) }^{ 0 }\quad +{ \Lambda  }^{ 0 } _{ \left( { H }^{ + } \right)  }$ 

Conductance $=\cfrac{kA}{l}$ 

Generally the conductivity of a solution increases with temperature, as the mobility of the ions increases.
Conductivity (or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity.
Electrolytic conductance generally increases with rise in temperature.

In metals, conductivity is due to movement of free electrons. When temperature increases, the vibration of metal ions increases. This results in increase in resistance of metal and hence, decrease in conductivity. In electrolytic conductors, the ions are charge carriers and with increase in temperature, ionization increases and hence, conductivity increases.

Increasing the temperature will inhibit conduction in a metallic conductors because the increased thermal motions of the electrons will tend to interfere with their regular flow in an electric current.

Molar conductivity at infinite dilution is the sum of the limiting molar conductivities of the cation and anion. For salt BA, we add the cation conductivity (180) and anion conductivity (220) to get 400 mhos cm² mol⁻¹. This additive property holds because at infinite dilution, ions behave independently without interionic interactions. The unit should be mol⁻¹, not mol⁻² as written in the question (a minor typographical error that doesn't affect the calculation).

the one which is having higher oxidation potential will undergo oxidation,

We have,