General
✓✗4.5 g of aluminium (atomic mass 27 u) is deposited at the cathode from an Al3+ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP (molar volume 22.4 L) from H+ ions in solution by the same quantity of charge will be
- 22.4 L
- 5.6 L
- 11.2 L
- 44.8 L
General
✓✗The conductivity of a 0.1 M KCl solution at 23 °C is 0.012 S cm−1. The resistance of the cell containing the solution at the same temperature was found to be 55 ohm. The cell constant will be
- 1.12 cm−1
- 1.142 cm−1
- 0.918 cm−1
- 0.66 cm−1
General
✓✗In the electrolysis of aqueous NaCl (brine) with inert electrodes, the product at the cathode is
- oxygen gas
- chlorine gas
- hydrogen gas
- sodium metal
General
✓✗The molar conductivity of 0.007 M acetic acid is 20 S cm2 mol−1. What is the dissociation constant of acetic acid? (Take λ°H+ = 350 S cm2 mol−1 and λ°CH3COO− = 50 S cm2 mol−1, and use Ka ≈ cα2.)
- 1.75 × 10−4 mol L−1
- 2.50 × 10−5 mol L−1
- 1.75 × 10−5 mol L−1
- 2.50 × 10−4 mol L−1
General
✓✗The conductivity of an electrolytic solution generally increases with increase in temperature because
- the cell constant increases
- electrons start moving
- ionic mobility increases (viscosity decreases)
- the solvent evaporates
General
✓✗The overall reaction of a lead storage battery during discharge is
- Pb + 2H2SO4 → Pb(SO4)2 + 2H2
- PbO + H2SO4 → PbSO4 + H2O
- Pb + PbO2 + 2H2SO4 → 2PbSO4 + 2H2O
- 2PbSO4 + 2H2O → Pb + PbO2 + 2H2SO4
General
✓✗In the electrolysis of brine (aqueous NaCl), the solution near the cathode becomes
- alkaline (NaOH forms)
- saturated with Cl2
- acidic
- neutral
General
✓✗When 0.1 F of electricity is passed through molten Al2O3 (dissolved in cryolite), the mass of aluminium deposited (100% efficiency) is
- 2.70 g
- 0.90 g
- 1.35 g
- 8.10 g
General
✓✗A device that converts the energy of combustion of fuels such as hydrogen and methane directly into electrical energy is known as
- a Ni−Cd cell
- a fuel cell
- an electrolytic cell
- a dynamo
General
✓✗The cell constant of a conductivity cell is
- l × A
- R/κ
- A/l
- l/A
General
✓✗The resistance of a conductivity cell is measured using
- a voltmeter only
- a DC source
- an AC source (Wheatstone bridge) to avoid electrolysis
- a galvanometer with DC
General
✓✗The standard Gibbs energy of a cell reaction is related to the equilibrium constant by
- ΔG° = −2.303RT log K
- ΔG° = −nF log K
- ΔG° = 2.303RT log K
- ΔG° = −RT/log K
General
✓✗The degree of dissociation of a weak acid whose molar conductivity is 39 S cm2 mol−1 and limiting molar conductivity is 390 S cm2 mol−1 is
- 0.10
- 0.39
- 1.00
- 0.01
General
✓✗The value of E° for Cu2+/Cu is +0.34 V and for Cu+/Cu is +0.52 V. Cu+ in aqueous solution tends to
- reduce Cu2+
- oxidise water
- disproportionate into Cu2+ and Cu
- be stable
General
✓✗Statement I: In the Daniell cell, Zn is the anode.
Statement II: In an electrolytic cell, the anode is the positive electrode.
Statement II: In an electrolytic cell, the anode is the positive electrode.
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
- Statement I is correct but Statement II is incorrect
- Statement I is incorrect but Statement II is correct