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Correct option (1, 2) 

Explanation:

In a galvanic cell, the salt bridge does not participate in the cell reaction, stops diffusion of ions from one electrode to another and is not necessary for the occurrence of the cell reaction.

It is a Rechargeable battery. Used in automobiles and inverters, Rechargeable batteries used in house hold appliances etc. 

(i) At cathode: 

The following reduction reactions compete to take place at the cathode 

Ag⁺(aq) + e^- → Ag(s); E^θ = 0.80 V 

H⁺ (aq) + e^- → H₂ (g); E^θ = 0.00V 

The reaction with a higher value of E^θ takes place of the cathode. 

Therefore, deposition of silver will take place at the cathode. 

At anode: The Ag anode is attacked by NO^3- ions. 

Therefore, the silver electrode at the anode dissolves in the solution to form Ag⁺. 

(ii) At cathode: Same as above At anode: Anode is not attackable and hence OH^- ions have lower discharge potential than NO^3- ions and OH^- ions react to give O₂ 

OH^- → OH + e^- 

4OH → 2H₂O + O₂ (g)

(iii) H₂SO₄ → 2H⁺ + SO₂^-4 

HO₂ ⇌ H⁺ + OH^- 

At cathode: 

2H⁺ + 2e^- → H₂ 

At anode: 4OH^- → 2H₂O + O₂ + 4e^- 

i. e., H₂ will be liberated at cathode and O₂ at anode. 

(iv) CuCl₂ → Cu²⁺ + 2Cl^- 

At Cathode: Cu²⁺ ions will be reduced in preference to H⁺ ions 

Cu²⁺ + 2e → Cu At anode: Cl^- ions will be oxidised in preference to OH^- ions. 

2Cl^- → Cl₂ + 2e^- 

i.e., Cu will be deposited on the cathode and Cl₂ will be liberated at the anode.

This cell is based on the combustion of fuel like Hydrogen by oxygen is called fuel cell.

A solution of NaCl shows greater conduction of electricity at a temperature of 50°C than at room temperature because the ionic mobility of a strong electrolyte such as NaCl increases with an increase in temperature.

Molar conductivity and specific conductivity are related to each other by the given equation.

\(\triangle_m = K \times \frac{1000}{C}\)

Where, 

Δ_m = Molar conductivity 

K = Specific conductivity 

C = Molar concentration

If k is conductivity and ∧_m is molar conductivity then,

∧_m = \(\frac{k \times 1000}{C}\)

Unit of molar conductivity is, Ω^-1 cm² mol or S cm² mol^-1.

Electrochemical series (Electromotive series) : It is defined as the arrangement in a series of electrodes of elements (metal or non-metal in contact with their ions) with the electrode half reactions in the decreasing order of their standard reduction potentials.

The conventions used in the construction of electrochemical series (or electromotive series) are as follows :

• The (reduction) electrodes or half cells of the elements are written on the left hand side of the series and they are arranged in the decreasing order of their standard reduction potentials (E°red).
• Reduction half reactions are written for each half cell in such a way that the species with higher oxidation state and electrons are on left hand side while reduced species with lower oxidation state are on right hand side.
• The standard reduction potential of standard hydrogen electrode is 0.00 V, i.e., \(E^0_{H^+/H_2}\) = 0.0 V. The electrodes and half cell reactions with positive E⁰_red values are located above hydrogen and those with negative E⁰_red  values below hydrogen. Above hydrogen, positive E⁰_red values increase, while below hydrogen negative E⁰ values increase.
• The positive E⁰_red values indicate the tendency for reduction and the negative E⁰_red values indicate the tendency for oxidation.
• The elements, whose electrodes are at the top of the series having high positive values for E⁰_red are good oxidising agents.
• The elements, whose electrodes are at the bottom of the series having high negative values for E⁰_red are good reducing agents. 

(1) According to IUPAC conventions, the electrode of the galvanic cell where electronation or reduction takes place is called cathode. In this, the electrons from the metal electrode are removed by cations required for their reduction.

\(Cu^{2+}_{(aq)}\) + 2e^- → Cu_(s)

(2) Since the electrons are lost, the metal electrode acquires a positive charge. Hence cathode in the galvanic cell is considered to be positive.

1. According to IUPAC conventions, 

The electrode of a galvanic cell where de-electronation or oxidation takes place releasing electrons is called anode.

Zn_(s) → \(Zn^{2+}_{(aq)}\) + 2e^-

2. The electrons released due to oxidation reaction are accumulated on the metal electrode surface charging it negatively.

Hence anode in the galvanic cell is considered to be negative.