Electrochemistry

The highest electrical conductivity of the following aqueous solutions is of :

Consider the following standard electrode potentials (E^o in volts) in aqueous solution : .tg {border-collapse:collapse;border-spacing:0;} .tg td{font-family:Arial, sans-serif;font-size:14px;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg th{font-family:Arial, sans-serif;font-size:14px;font-weight:normal;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg .tg-wv9z{font-size:22px;text-align:center} .tg .tg-de48{font-weight:bold;font-size:22px;text-align:center} Element M³⁺ /M M⁺ /M A1 -1.66 + 0.55 T1 +1.26 - 0.34 Based on these data, which of the following statements is correct ?

The Gibbs energy for the decomposition of Al₂O₃ at 500^oC is as follows : ${2 \over 3}A{l_2}{O_3}$ $\to$ ${4 \over 3}Al + {O_2}$, ${\Delta _r}G$ = + 966 kJ mol^–1 The potential difference needed for electrolytic reduction of Al₂O₃ at 500^oC is at least :

For lead storage battery pick the correct statements A. During charging of battery, $\mathrm{PbSO}_{4}$ on anode is converted into $\mathrm{PbO}_{2}$ B. During charging of battery, $\mathrm{PbSO}_{4}$ on cathode is converted into $\mathrm{PbO}_{2}$ C. Lead storage battery consists of grid of lead packed with $\mathrm{PbO}_{2}$ as anode D. Lead storage battery has $\sim 38 \%$ solution of sulphuric acid as an electrolyte Choose the correct answer from the options given below:

.tg {border-collapse:collapse;border-spacing:0;} .tg td{font-family:Arial, sans-serif;font-size:14px;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg th{font-family:Arial, sans-serif;font-size:14px;font-weight:normal;padding:10px 5px;border-style:solid;border-width:1px;overflow:hidden;word-break:normal;border-color:black;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-uys7{border-color:inherit;text-align:center} .tg .tg-xldj{border-color:inherit;text-align:left} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} Electrolyte: KCl KNO₃ HCl NaOAc NaCl ${ \wedge ^\infty }(Sc{m^2}mo{l^{ - 1}}):$ 149.9 145 426.2 91 126.5 Calculate $\wedge _{HOAc}^\infty$ Using appropriate molar conductances of the electrolytes listed above at infinite dilution in H₂O at 25^oC

Which of the following statements is not correct about rusting of iron?

Several blocks of magnesium are fixed to the bottom of a ship to :

In a hydrogen – oxygen fuel cell, combustion of hydrogen occurs to :

The molar conductivities $\wedge _{NaOAc}^o$ and $\wedge _{HCl}^o$ and at infinite dilution in water at 25^oC are 91.0 and 426.2 Scm²/mol respectively. To calculate $\wedge _{HOAc}^o$ , the additional value required is

In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is CH₃OH(l) + 3/2O_2 $\to$ CO₂ (g) + 2H₂O (l) At 298K standard Gibb’s energies of formation for CH₃OH(l), H₂O(l) and CO₂ (g) are -166.2, -237.2 and -394.4 kJ mol^−1 respectively. If standard enthalpy of combustion of methanol is -726 kJ mol^−1, efficiency of the fuel cell will be

Galvanization is applying a coating of :

Identify the correct statement :

Compound A used as a strong oxidizing agent is amphoteric in nature. It is the part of lead storage batteries. Compound A is :

Match List - I with List - II. .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-fymr{border-color:inherit;font-weight:bold;text-align:left;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} List - I List - II (A) $Cd(s) + 2Ni{(OH)_3}(s) \to CdO(s) + 2Ni{(OH)_2}(s) + {H_2}O(l)$ (I) Primary battery (B) $Zn(Hg) + HgO(s) \to ZnO(s) + Hg(l)$ (II) Discharging of secondary battery (C) $2PbS{O_4}(s) + 2{H_2}O(l) \to Pb(s) + Pb{O_2}(s) + 2{H_2}S{O_4}(aq)$ (III) Fuel cell (D) $2{H_2}(g) + {O_2}(g) \to 2{H_2}O(l)$ (IV) Charging of secondary battery Choose the correct answer from the options given below:

The equivalent conductance of NaCl at concentration C and at infinite dilution are ${\lambda _C}$ and ${\lambda _\infty }$, respectively. The correct relationship between ${\lambda _C}$ and ${\lambda _\infty }$ is given as: (where the constant B is positive)

Two Faraday of electricity is passed through a solution of CuSO₄. The mass of copper deposited at the cathode is: (at. mass of Cu = 63.5 amu)

Match List I with List II .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-c3ow{border-color:inherit;text-align:center;vertical-align:top} .tg .tg-7btt{border-color:inherit;font-weight:bold;text-align:center;vertical-align:top} .tg .tg-0pky{border-color:inherit;text-align:left;vertical-align:top} LIST I (Cell) LIST II (Use/Property/Reaction) A. Leclanche cell I. Converts energy of combustion into electrical energy B. Ni - Cd cell II. Does not involve any ion in solution and is used in hearing aids C. Fuel cell III. Rechargeable D. Mercury cell IV. Reaction at anode $\mathrm{Zn} \rightarrow \mathrm{Zn}^{2+}+2 \mathrm{e}^{-}$ Choose the correct answer from the options given below :

Fuel cell, using hydrogen and oxygen as fuels, A. has been used in spaceship B. has as efficiency of $40 \%$ to produce electricity C. uses aluminum as catalysts D. is eco-friendly E. is actually a type of Galvanic cell only Choose the correct answer from the options given below:

The reaction at cathode in the cells commonly used in clocks involves.