# TN 12TH PHYSICS (Test 1)

Tag: tn 12th physics
Q.1
For a first order reaction A → B the rate constant is x min1 . If the initial concentration of A is 0.01M , the concentration of A after one hour is given by the expression.
A. 0.01 e−x
B. 1 x10-2 (1-e-60x)
C. (1x10-2) e-60x
D. none of these
Explaination / Solution: In this case

k = x min−1 and [A0] = 0.01M = 1 × 10−2M

t = 1 hour = 60 min

[A]= 1 × 10−2 ( e−60x)

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Q.2
What is the activation energy for a reaction if its rate doubles when the temperature is raised from 200K to 400K? (R = 8.314 JK-1mol-1)
A. 234.65 kJ mol1K1
B. 434.65 kJ mol1K1
C. 434.65 J mol1K1
D. 334.65 J mol1K1
Explaination / Solution:

T1 = 200K ; k = k1

T2 = 400K ; k = k2 = 2k1 Workspace
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Q.3
In a homogeneous reaction A →B + C + D , the initial pressure was P0 and after time t it was P. expression for rate constant in terms of P0, P and t will be
A. B. C. D. Explaination / Solution: Workspace
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Q.4
In calcium fluoride, having the flurite structure the coordination number of Ca2+ ion and F- Ion are
A. 4 and 2
B. 6 and 6
C. 8 and 4
D. 4 and 8
Explaination / Solution:

CaF2 has cubical close packed arrangement

Ca2+ ions are in face centered cubic arrangement, each Ca2+ ions is  surrounded by 8 F ions and each F ion is surrounded by 4 Ca2+ ions.

Therefore coordination number of Ca2+ is 8 and of F  is 4

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Q.5
The fraction of total volume occupied by the atoms in a simple cubic is
A. π / 4√2
B. π / 6
C. π / 4
D. π / 3√2
Explaination / Solution: Workspace
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Q.6
The sum of primary valance and secondary valance of the metal M in the complex [ M ( en)2 ( Ox)] Cl is L
A. 3
B. 6
C. -3
D. 9
Explaination / Solution:

In the complex [M (en)2 (Ox)] Cl For the central metal ion M3+

The primary valance is = +3

The secondary valance = 6

sum of primary valance and secondary valance = 3+6 = 9

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Q.7
Which type of isomerism is exhibited by Pt ( NH3)2 Cl2 ?
A. Coordination isomerism
C. Optical isomerism
D. Geometrical isomerism
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Q.8
Sc( Z=21) is a transition element but Zinc (z=30) is not because
A. both Sc3+ and Zn2+ ions are colourless and form white compounds.
B. in case of Sc, 3d orbital are partially filled but in Zn these are completely filled
C. last electron as assumed to be added to 4s level in case of zinc
D. both Sc and Zn do not exhibit variable oxidation states
Explaination / Solution:
No Explaination.

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Q.9
In acid medium, potassium permanganate oxidizes oxalic acid to
A. oxalate
B. Carbon dioxide
C. acetate
D. acetic acid
Explaination / Solution:

5(COO)22- + 2MnO 4 + 16H+ → 2Mn2+ + 10CO2 + 8H2O

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Q.10
Which of the following oxidation states is most common among the lanthanoids?
A. 4
B. 2
C. 5
D. 3