Multiple Choice QuestionsIf a gas expands at constant temperature, it indicates that
the kinetic energy of molecules decrease
the pressure of the gas increases
the kinetic energy of molecules remains the same
the kinetic energy of molecules remains the same
C.
the kinetic energy of molecules remains the same
The angular shape of ozone molecule (O3) consists of
1 sigma and 2 pi bonds
2 sigma and 2 pi bonds
1 sigma and 1 pi bonds
1 sigma and 1 pi bonds
D.
1 sigma and 1 pi bonds
Single bond contains = 1 σ bond
Double bond contains = 1 σ bond + 1 π bond
Triple bond contains = 1σ bond + 2 π bond
The molecule of O3 is bent with an angle of 116.8o and equal O-O distance of 128 pm. The ozone molecule consists of 2 sigma bond and 1 pi bond.
If uncertanity in position and momentum are equal, then uncertaninty in velocity is
A.
According to Heisenberg's uncertainty principle, it is impossible to determine simultaneously the position and momentum of moving a particle, ie.
The uncertainty principle in terms of energy and time is given as
Number of moles of MnO4- required to oxidies one mole of ferrous oxalate completely in acidic medium will be
0.6 mole
0.4 mole
7.5 mole
7.5 mole
A.
0.6 mole
The correct order of decreasing second ionisation enthalpy of Ti (22), V (23), Cr(24) and Mn (25) is
Cr > Mn> V > Ti
V > Mn > Cr >Ti
Mn > Cr> Ti >V
Mn > Cr> Ti >V
A.
Cr > Mn> V > Ti
The amount of energy required to remove an electron from unipositive ions is called the second IP which generally increases in a period from left to right.
The second ionisation energies of the first transition series increase almost regularly with an increase in atomic number. However, the value for Cr is sufficiently higher than those of its neighbour ie, (Mn). This is due to the stable configuration of Cr3+ (3d5 exactly half filled.)
[Note: The half-filled and completely filled configuration are more stable.]
Equal volumes of three acid solutions of pH 3.4 and 5 are mixed in a vessel. What will be the H+ ion concentration in the mixture?
1.11 x 10-4 M
3.7 x 10-4 M
3.7 x 10-3 M
3.7 x 10-3 M
B.
3.7 x 10-4 M
[H]+ in mixture
[H]+ of 1st acid x its volume + [H+]
of IInd acid x its volume + [H+] of 
Assume the volume of each solution is 1 L.
[H3O+] in solution of pH = 3 is 10-3M
[H3O+] in solution of pH = 4 is 10-4 M
[H3O+] in solution is pH is 5 is 10-5 M
For the gas phase, reaction,
PCl5 (g) ⇌ PCl3 (g) Cl2 (g)
Which of the following conditions are correct?
Δ H = 0 and ΔS > 0
ΔH >0 and ΔS > 0
Δ H < 0 and ΔS < 0
Δ H < 0 and ΔS < 0
B.
ΔH >0 and ΔS > 0
ΔH = ΔE + ΔnRT
Δn = number of moles of product - number of moles of reactants
ΔG = ΔH - TΔS
For a spontaneous process, ΔG must be negative
PCl5 (g) ⇌ PCl3 (g) Cl2 (g)
In this reaction
Δn = 2-1 = 1
Thus, ΔH is positive, ie, >0
If ΔH is positive, then to maintain the value of ΔG negative, ΔS should be positive , ie, ΔS>0.
Which of the following are not state functions?
I) q + W
II) q
III) W
IV) H-TS
(I) and (IV)
(II) (III) and (IV)
(I), (II) and (III)
(I), (II) and (III)
D.
(I), (II) and (III)
A state function is the property of the system whose value depends only on the initial and final state of the system and is independent of the path.
Therefore,
Internal energy (ΔE) = q +W
It is a state function because it is independent of the path. It is an extensive property.
∴ Gibbs energy (G) = H -TS
It is also a state function because it is independent of the path. It is also extensive property.
Heat (q) and work (W) are not state functions being path dependent.
If the concentration of OH- ions in the reaction Fe(OH)3 (s) ⇌ Fe3+ (aq) + 3OH-(aq) is decreased by 1/4 times, then equilibrium concentration of Fe3+ will increase by
8 times
16 times
64 times
64 times
C.
64 times
The concentration of solids taken to be unity.
Fe(OH)3 (s) ⇌ Fe3+ (aq) + 3OH- (aq)
therefore,
K = [Fe3+][OH-]3
Hence, if OH- ion concentration is decreased by 1/4 times. then equilibrium concentration of Fe3+ will increase by 64 times.
The sequence of ionic mobility in aqueous solution is
K+ > Na+ > Rb+ > Cs+
Cs+ > Rb+ > K+ >Na+
Rb+ > K+> Cs+ > Na+
Rb+ > K+> Cs+ > Na+
B.
Cs+ > Rb+ > K+ >Na+
The smaller the size of ion, the greater the degree of hydration.
Generally in a group size or radii of ions increases, So Li has the smallest size thus bind a maximum number of water molecules with itself and becomes largest in size (in aqueous solution). Hence, the order of ionic radii (size) of alkali metal ions in aqueous solution is
Li+ > Na+ > K+> Rb+ >Cs+
Thus, the order of mobility
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