Multiple Choice QuestionsFor a given reaction, ΔH = 35.5 kJ mol–1 and ΔS = 83.6 JK–1 mol–1. The reaction is spontaneous at (Assume that ΔH and ΔS do not vary with temperature)
T < 425 K
T > 425 K
All temperatures
All temperatures
B.
T > 425 K
∵ ΔG = ΔH – TΔS
For a reaction to be spontaneous, ΔG = –ve
i.e., ΔH < TΔS
therefore, T> ΔH/ΔS
= 35.5 x 103J/83.6JK-1
i.e T>425 K
The element Z = 114 has been discovered recently. It will belong to which of the following family group and electronic configuration?
Halogen family, [Rn] 5f14 6d10 7s2 7p5
Carbon family, [Rn] 5f14 6d10 7s2 7p2
Oxygen family,[Rn] 5f14 6d10 7s2 7p4
Oxygen family,[Rn] 5f14 6d10 7s2 7p4
B.
Carbon family, [Rn] 5f14 6d10 7s2 7p2
Z = 114 belong to Group 14, carbon family Electronic configuration , [Rn] 5f14 6d10 7s2 7p2
Which of the following pairs of compounds is isoelectronic and isostructural?
BeCl2, XeF2
Tel2, XeF2
IBr2- , XeF
IBr2- , XeF
C.
IBr2- , XeF
IBr2–, XeF2
The total number of valence electrons are equal in both the species and both the species are linear also.
With respect to the conformers of ethane, which of the following statements is true?
Bond angle remains same but bond length changes
Bond angle changes but bond length remains same
Both bond angle and bond length change
Both bond angle and bond length change
D.
Both bond angle and bond length change
There is no change in bond angles and bond lengths in the conformations of ethane. There is only change in dihedral angle.
HgCl2 and I2 both when dissolved in water containing I– ions the pair of species formed is
HgI2 , I3-
Hgl2, I-
HgI43-, I3-
HgI43-, I3-
C.
HgI43-, I3-
In a solution containing HgCl2, I2 and I–, both HgCl2 and I2
compete for I–.
Since formation constant of [HgI4]2– is 1.9 × 1030
which is very large as compared with I3– (Kf= 700)
therefore, I– will preferentially combine with HgCl2
HgCl2 + 2l- → Hgl2↓ + 2Cl-
Hgl2 + 2l- → [Hgl4]2-
A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy ΔU of the gas in joules will be
1136.5 J
-500 J
-505 J
-505 J
C.
-505 J
ΔU = q + w
For adiabatic process, q = 0
∴ ΔU = w
= – P·ΔV
= –2.5 atm × (4.5 – 2.5) L
= –2.5 × 2 L-atm
= –5 × 101.3 J
= –506.5 J
= –505 J
20-litre container at 400 K contains CO2(g) at pressure 0.4 atm and an excess of SrO (neglect the volume of solid SrO). The volume of the containers is now decreased by moving the movable piston fitted in the container. The maximum volume of the container, when pressure of CO2 attains its maximum value, will be
Given that: SrCO3 ⇌ SrO(s) + CO2(g) kp = 1.6 atm)
5 litre
10 litre
8 litre
8 litre
A.
5 litre
Max. the pressure of CO2= Pressure of CO2 at equilibrium
For reaction, SrCO3 ⇌ SrO(s) + CO2(g)
Kp= PCO2 = 1.6 atm = maximum pressure of CO2
Volume Container at this stage,
V= nRT/P .... (i)
Since container is sealed and reaction was not earlier at equilibrium
therefore, n = constant
n= Pv/RT .... (ii)
from equation (i) and (ii) we get
V = (0.4 x 20)/RT = 5 Litre
The correct statement regarding electrophile is
Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from a nucleophile
Electrophile is a negatively charged species and can form a bond by accepting a pair of electrons from another electrophile
Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile
Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile
D.
Electrophiles are generally neutral species and can form a bond by accepting a pair of electrons from a nucleophile
Match the interhalogen compounds of column I with the geometry in column II and assign the correct code
| Column I | Column II |
| a) XX' | (i) T-shape |
|
b) XX3' |
(ii) Pentagonal |
|
c) XX'5 |
(iii) Linear |
| d) XX'7 | (iv) Square-pyramidal |
| (v) Tetrahedral |
| (a) | (b) | (c) | (d) |
| (iii) | (iv) | (i) | (ii) |
| (a) | (b) | (c) | (d) |
| (iii) | (i) | (iv | (ii) |
| (a) | (b) | (c) | (d) |
| (iv) | (v) | (iii) | (ii) |
| (a) | (b) | (c) | (d) |
| (iv) | (v) | (iii) | (ii) |
B.
| (a) | (b) | (c) | (d) |
| (iii) | (i) | (iv | (ii) |
Which one is the wrong statement?
de-Broglie's wavelength is given by λ = h/mv,
where m = mass of the particle, v = group velocity of the particle
The uncertainty principle is 
Half-filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement
Half-filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement
D.
Half-filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement
