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During discharging of lead storage battery, which of the following is/are true?
Pb(s) + PbO2 + 2H2SO4 → 2PbSO1 (s) + 2H2O
H2SO4 : consumed
H2O : produced (volume increases and density decreases)
Anode
Pb (S) + SO42+ → PbSO4 + 2e–
Cathode
2e– + 4H+ + PbO2 + So42– → PbSO4 (s) + 2H2O
Which of the following arrangement will produce oxygen at anode during electrolysis?
(A) At anode oxidation of Cu produce Cu2+
(B) At both electrode oxidation or reduction of hydrogen or H+
(C) At anode
4OH– → O2 + 2H2O + 4e–
(D) Anode
2H2O → 4H+ + O2 + 4e–
If 270.0 g of water is electrolysed during an experiment performed by miss abhilasha with 75% current efficiency then
Cell reaction
equivalent = 15 × 2 = 30 equivalent
Total volume of gas produced
(c) H2 produced = 30 × 22.4 = 336 L
at cathode current efficilency = 75%
(d) for 30 F electricity consumed
Pick out the correct statements among the following from inspection of standard reduction potentials (Assume standard state conditions).
(a) SOP (SO42–) = –2.00
SOP (Cl–) = – 1.36
oxidation of SO42– will not take place
(b) SOP (Cl–) = – 13.6
SOP (I–) = –0.54
SOP (Br–) = –1.09
(c) Similarly as (b) option
(d) Br– can’t be reduced further.
The EMF of the following cell is 0.22 volt.
Ag(s) |AgCl(s)|KCl(1M)|H+(1M)|H2(g) (1atm); Pt(s)
Which of the following will decrease the EMF of cell.
Cell reaction
Anode
Ag(s) + Cl–1 → AgCl (s) + e–
Cathode 2H+ + 2e– → H2
Equal volumes of 0.015 M CH3COOH & 0.015 M NaOH are mixed together. What would be molar conductivity of mixture if conductivity of CH3COONa is 6.3 × 10-4 S cm-1
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement-1 : The voltage of mercury cell remains constant for long period of time.
Statement-2 : It is because net cell reaction des not involve active species.
HgO Cathode ; Zn (anode)
Zn → Zn2+ + 2e–
Hg2+ + 2e– → Hg
Cell reaction
Zn + HgO → ZnO + Hg
No active species in cell reactions
⇒ no change in cell voltage.
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement-1 : The SRP of three metallic ions A+, B2+, C3+ are -0.3, -0.5, 0.8 volt respectively, so oxidising power of ions is C3+ > A+ > B2+
Statement-2 : Higher the SRP, higher the oxidising power.
SRP increases ⇒ The tendency to getting reduced increases and the oxidizing power increases.
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement-1 : We can add the electrode potential in order to get electrode potential of net reaction.
Statement-2 : Electrode potential is an intensive property.
We can add only when the net reaction does not contain any electron [E.P. is an intensive property]
The questions given below consist of Statement– I and Statement – II. Use the following Key to choose the appropriate answer.
Statement - I. In electrolysis, the quantity of electricity needed for depositing 1 mole of silver is different form that required for 1 mole of copper.
Statement - II. The atomic weights of silver and copper are different.
Statement I : is correct as the n factor of both silver and copper are different so the gm equivalent of electricity required will be different .
Statement II : It is also correct that atomic weight of siliver and copper are different but statement II is not the reight explanation of I. So answer (B).
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement - I. CuSO4 solution cannot safely be kept in a Zn vessel usual.
Statement - II. The position of Zn is lower than Cu in Electro-chemical-series.
Statement I : is correct beause copper lies at higher position in electrichenical sesier so upper will start deposition in vessel.
Statement II : It is false because copper is at higher position so Ans (C)
The questions given below consist of Statement – I and Statement– II. Use the following Key to choose the appropriate answer.
Statement - I. Zinc displaces copper from copper sulphate solution..
Statement - II. The Eº is Zn of –0.76 volt and that of copper is +0.34 volt.
Statement I is correct because
Zn + CuSO4 → Cu + ZnSO4 Zinc oxidation takes place and reduction of copper take blake.
Statement II : Is also correct and given values are correct So Ans. (A)
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement - I. Gold chloride (AuCl3) solution cannot be stored in a vessel made of copper, iron, nickel, chromium, zinc or tin.
Statement - II. Gold is very precious metal.
Statement I : It is correct as gold has higher reduction potential.
Statement II : It is also correct but not the correct explanation of I.
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement - I . Specific conductance decreases with dilution whereas equivalent conductance increases.
Statement - II. On dilution, number of ions per cc decreases but total number of ions increases considerably.
Statement I : It is correct
λ = KV
K = λ/V
thus inversely proportional.
Statement II : It is also correct because number of ions per CC decreases and also correct explation of I.
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement - I. Salt bridge is used in Electro chemical cell.
Statement - II. The ions of the electrolyte used in salt bridge should have almost same ionic mobility.
Statement I : It is correct
Statement II : It is correct but not the correct explanation of above
The questions given below consist of Statement – I and Statement – II. Use the following Key to choose the appropriate answer.
Statement - I. Absolute value of an electrode potential can not be calculated.
Statement - II. Neither oxidation nor reduction can take place alone.
Statement I : Assolute value can’t be calculated it is only calculated W.r.t. hydrogen.
Statement II : It is wrong
Comprehension
Paragraph -1
A sample of water from a large swimming pool has a resistance of 10000 ohm at 25ºC when placed in a certain conductance cell. When filled with 0.02 M KCl solution, the cell has a resistance of 100 ohm at 25ºC. 585 gm of NaCl were dissolved in the pool, which was throughly stirred. A sample of this solution gave a resistance of 8000 Ω.
[Given : Molar conductance of NaCl at that concentration is 125 ohm-1cm2mol-1 and molar conductivity of KCl at 0.02 M is 200 Ω-1cm2 mol-1.]
Q.
Cell constant (in cm-1) of conductance cell is :
A sample of water from a large swimming pool has a resistance of 10000 ohm at 25ºC when placed in a certain conductance cell. When filled with 0.02 M KCl solution, the cell has a resistance of 100 ohm at 25ºC. 585 gm of NaCl were dissolved in the pool, which was throughly stirred. A sample of this solution gave a resistance of 8000 Ω.
[Given : Molar conductance of NaCl at that concentration is 125 ohm-1cm2mol-1 and molar conductivity of KCl at 0.02 M is 200 Ω-1cm2 mol-1.]
Q.
Conductivity (Scm-1) of H2O is :
A sample of water from a large swimming pool has a resistance of 10000 ohm at 25ºC when placed in a certain conductance cell. When filled with 0.02 M KCl solution, the cell has a resistance of 100 ohm at 25ºC. 585 gm of NaCl were dissolved in the pool, which was throughly stirred. A sample of this solution gave a resistance of 8000 Ω.
[Given : Molar conductance of NaCl at that concentration is 125 ohm-1cm2mol-1 and molar conductivity of KCl at 0.02 M is 200 Ω-1cm2 mol-1.]
Q.
Volume (in Litres) of water in the pool is:
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