Which of the following ions has the highest value of ionic radius:
O2-
F-
Li+
B3+
A.
O2-
O2- has the highest value of ionic radius and this can be explained on the basis of (nuclear charge / number of electrons) ratio. when ratio increases the size decreases and when ratio decreases , the size increases.
A cylinder of compressed gas contains nitrogen and oxygen in the ratio of 3:1 by mole. The total mass of the gas mixture if the cylinder is known to contain 2.5 x 104 g of oxygen will be:
8 x 103 g
9 x 104 g
9 x 103 g
8 x 102 g
B.
9 x 104 g
Number of moles of oxygen in the cylinder
=
= = 781.25
Number of moles of N2 = 3 x 781.25
=2343.75
Mass of nitrogen in cylinder
=6.5625 x 104 g
Hence , the total mass of gas cylinder
= 2.5 x 104 + 6.56259 x 104
= 9.0625 x 104 g
On adding A to the reaction at equilibrium, AB (s) A(g) + B(g) the new equilibrium concentration of A becomes double, the equilibrium concentration of B would become:
1/2 of its original value
1/4 of its original value
1/8 of its original value
Twice its original value
A.
1/2 of its original value
Kc =
Now , if [A] = 2 [A] , B should be [B].
So , that Kc remains constant.
The entropy will be positive in which of the following reaction change.
H2(g) + I2 (g) 2HI (g)
HCl(g) + NH3 (g) N2O(g) + 2H2O(g)
NH4NO3(s)N2O(g) + 2H2O(g)
MgO(s) + H2(g) Mg(s) + H2O(l)
C.
NH4NO3(s)N2O(g) + 2H2O(g)
Entropy is a measure of randomness of the system, so entropy of substance in different physical states is in the order Gas > Liquid > Solid
S=Sproduct -Sreactant
In option (c), solid is converted into gaseous state, so S will be positive.
The vapour pressure of pure water is 25.0 mm Hg and that of an aqueous dilute solution of urea in 20mm Hg at 25°C. The molarity of the solution is:
12.6
14.9
13.8
9.6
C.
13.8
The given values are:
Using Raoult's law
Substituting the values:
=1-0.2=0.8
Assuming that Hund's rule in violated,the bond order and magnetic nature of the diatomic molecule B2 is:
1 and diamagnetic
0 and diamagnetic
1 and paramagnetic
O and paramagnetic
A.
1 and diamagnetic
B2 : Total electrons = 10
Configuration :
If Hund's rule is violated, then
So, diamagnetic bond order = = 1
Wave number of a spectral line for a given transition is xcm-1 for He+ then its value for Be+ (iso electronic of H+) for same transition is:
x cm-1
4x cm-1
cm-1
2x cm-1
B.
4x cm-1
=(wave number)
=RHZ2
(He+ , z=2)=RH(22)
v2( , z=4)=RH(42)
v2=4v1=4x
A solution contains 10 mL of 0.1 N NaOH and 10mL of 0.05 NH2SO4.pH of this solution is:
zero
less than 7
greater than 7
7
C.
greater than 7
Number of milliequivalents of NaOH = 0.1 x 10 = 1
Number of milliequivalents of H2SO4
= 10 x 0.05 = 0.5
Milliequivalent of H2SO4 will neutralise NaOH so that (1-0.5) = 0.5 milliequivalent of NaOH is left unneutralised.
Therefore, pH of the resulting solution will be greater than seven i.e., pH > 7,
The correct sets of quantum numbers which represents the highest energy level in an atomis:
D.
The order of energy of orbitals can be calculated from (n + 1) rule. The lower the value of (n +l) For an orbital, lower is its energy. If two orbitals have same (n+J) value, the orbital with lower value of n has lower energy.
(a) n+l = 4 (b) n+l = 3
(c) n+l = 4 (d) n+l = 4
The correct set which represents the highest energy level is n = 3 , l = 2 , m = -2 and s = +
The hybridisation and shape of IF5 are respectively:
sp3d , trigonal bipyramide
sp3d , see saw
sp3d , square pyramidal
sp3d , pentagonal pyramidal
C.
sp3d , square pyramidal
IF5 has 5 bond pair and 1 lone pair
The geometry is square pyramidal with sp3d hybridisation
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