Calculate the standard cell potentials of galvanic cells in which the following reactions take place:
(i) 2Cr(s) + 3Cd2+(aq) → 2Cr3+(aq) + 3Cd
(ii) Fe2+(aq) + Ag+(aq) → Fe3+(aq) + Ag(s)
Calculate the ΔrGø¸ and equilibrium constant of the reactions.
(i) Eø Cr3+ / Cr = - 0.74 V
Eø Cd2+ / Cd = - 0.40 V
The galvanic cell of the given reaction is depicted as:
Now, the standard cell potential is
Eø = EøR - EøL
= -0.40 - (-0.74)
= + 0.34 V
ΔrGø = -nFEøcell
In the given equation,
n = 6
F = 96487 C mol - 1
Eøcell = +0.34 V
Then, ΔrGø = - 6 × 96487 C mol - 1 × 0.34 V
= - 196833.48 CV mol - 1
= - 196833.48 J mol - 1
= - 196.83 kJ mol - 1
Again,
ΔrGø = - RT ln K
= 34.496
K = antilog (34.496)
= 3.13 × 1034
(ii) Eø Fe3+ / Fe2+ = 0.77 V
Eø Ag+ / Ag = 0.80 V
The galvanic cell of the given reaction is depicted as:
Now, the standard cell potential is
Eø = EøR - EøL
= 0.80 - 0.77
= 0.03 L
Here, n = 1.
Then, ΔrGø = -nFEøcell
= - 1 × 96487 C mol - 1 × 0.03 V
= - 2894.61 J mol - 1
= - 2.89 kJ mol - 1
Again, ΔrGø = - 2.303 RT ln K
= 0.5073
K = antilog (0.5073)
= 3.2 (approximately)
Give simple chemical tests to distinguish between the following pairs of compounds.
(i) Propanal and Propanone
(ii) Acetophenone and Benzophenone
(iii) Phenol and Benzoic acid
(iv) Benzoic acid and Ethyl benzoate
(v) Pentan-2-one and Pentan-3-one
(vi) Benzaldehyde and Acetophenone
(vii) Ethanal and Propanal
How the following conversions can be carried out?
(i) Propene to propan-1-ol
(ii) Ethanol to but-1-yne
(iii) 1-Bromopropane to 2-bromopropane
(iv) Toluene to benzyl alcohol
(v) Benzene to 4-bromonitrobenzene
(vi) Benzyl alcohol to 2-phenylethanoic acid
(vii) Ethanol to propanenitrile
(viii) Aniline to chlorobenzene
(ix) 2-Chlorobutane to 3, 4-dimethylhexane
(x) 2-Methyl-1-propene to 2-chloro-2-methylpropane
(xi) Ethyl chloride to propanoic acid
(xii) But-1-ene to n-butyliodide
(xiii) 2-Chloropropane to 1-propanol
(xiv) Isopropyl alcohol to iodoform
(xv) Chlorobenzene to p-nitrophenol
(xvi) 2-Bromopropane to 1-bromopropane
(xvii) Chloroethane to butane
(xviii) Benzene to diphenyl
(xix) tert-Butyl bromide to isobutyl bromide
(xx) Aniline to phenylisocyanide
Henry's law constant for CO2 in water is 1.67 x 108Pa at 298 K. Calculate the quantity of CO2in 500 mL of soda water when packed under 2.5 atm CO2 pressure at 298 K.
A solution of glucose in water is labelled as 10% w/w, what would be the molality and mole fraction of each component in the solution? If the density of solution is 1.2 g mL-1, then what shall be the molarity of the solution?
Calculate the mole fraction of benzene in solution containing 30% by mass in carbon tetrachloride.
The vapour pressure of pure liquids A and B are 450 and 700 mm Hg respectively, at 350 K. Find out the composition of the liquid mixture if total vapour pressure is 600 mm Hg. Also find the composition of the vapour phase.
A 5% solution (by mass) of cane sugar in water has freezing point of 271 K. Calculate the freezing point of 5% glucose in water if freezing point of pure water is 273.15 K.
H2S, a toxic gas with rotten egg like smell, is used for the qualitative analysis. If the solubility of H2S in water at STP is 0.195 m, calculate Henry's law constant.
Calculate the mass of a non-volatile solute (molar mass 40 g mol-1) which should be dissolved in 114 g octane to reduce its vapour pressure to 80%.
Calculate the mass of urea (NH2CONH2) required in making 2.5 kg of 0.25 molal aqueous solution.
Calculate the number of unpaired electrons in the following gaseous ions: Mn3+, Cr3+, V3+ and Ti3+. Which one of these is the most stable in aqueous solution?
Explain how rusting of iron is envisaged as setting up of an electrochemical cell.
Nitrogen exists as diatomic molecule and phosphorus as P4. Why?
Consider the reaction:
Cr2 O72- + 14H+ + 6e- → Cr3+ + 8H2O
What is the quantity of electricity in coulombs needed to reduce 1 mol of Cr2 O72-?
Draw figure to show the splitting of d orbitals in an octahedral crystal field.
Explain the following with an example.
(i) Kolbe's reaction.
(ii) Reimer-Tiemann reaction.
(iii) Williamson ether synthesis.
(iv) Unsymmetrical ether.
What are the factors which influence the adsorption of a gas on a solid?
What happens when sulphur dioxide is passed through an aqueous solution of Fe(III) salt?
Write structures of the compounds whose IUPAC names are as follows:
(i) 2-Methylbutan-2-ol
(ii) 1-Phenylpropan-2-ol
(iii) 3,5-Dimethylhexane -1, 3, 5-triol
(iv) 2,3 - Diethylphenol
(v) 1 - Ethoxypropane
(vi) 2-Ethoxy-3-methylpentane
(vii) Cyclohexylmethanol
(viii) 3-Cyclohexylpentan-3-ol
(ix) Cyclopent-3-en-1-ol
(x) 3-Chloromethylpentan-1-ol.
How will you distinguish between the following pairs of terms:
(i) Hexagonal close-packing and cubic close-packing?
(ii) Crystal lattice and unit cell?
(iii) Tetrahedral void and octahedral void?
Very helpful to me