Chemistry (Test 4)

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| Some Basic Concepts of Chemistry | | Structure of Atom | | Classification of Elements and Periodicity in Properties | | Chemical Bonding and Molecular Structure | | States of Matter | | Thermodynamics | | Equilibrium | | Redox Reactions | | Hydrogen | | The s-Block Elements | | The p-Block Elements | | Organic Chemistry Some Basic Principles and Techniques | | Hydrocarbons | | Environmental Chemistry | | Solid State | | Chemistry Solutions | | Electrochemistry | | Chemical Kinetics | | Surface Chemistry | | General Principles and Processes of Isolation of Elements | | The d- and f- Block Elements | | Coordination Compounds | | Haloalkanes and Haloarenes | | Alcohols Phenols and Ethers | | Aldehydes Ketones and Carboxylic Acids | | Organic compounds containing Nitrogen | | Biomolecules | | Polymers | | Chemistry in Everyday Life | | UNIT 1: Basic Concepts of Chemistry and Chemical Calculations | | UNIT 2: Quantum Mechanical Model of Atom | | UNIT 3: Periodic Classification Of Elements | | UNIT 4: Hydrogen | | UNIT 5: Alkali and Alkaline Earth Metals | | UNIT 6: Gaseous State | | UNIT 7: Thermodynamics | | Unit I: Metallurgy | | Unit II: p-Block Elements I | | Unit III: p-Block Elements II | | Unit IV: Transition and Inner Transition Elements | | Unit V: Coordination Chemistry | | Unit VI: Solid State | | Unit VII: Chemical Kinetics |
Q.1
For a first order reaction A → product with initial concentration x mol L1 , has a half life period of 2.5 hours . For the same reaction with initial concentration (x/2) mol L1 the half life is
A. (2.5 × 2) hours
B. (2.5 / 2) hours
C. 2.5 hours
D. Without knowing the rate constant, t1/2 cannot be determined from the given data
Answer : Option D
Explaination / Solution:

For a first order reaction

t1/2 = 0.693/k

t1/2 does not depend on the initial concentration and it remains constant (whatever may be the initial concentration)

t1/2 = 2.5 hrs


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Q.2
In a first order reaction x → y ; if k is the rate constant and the initial concentration of the reactant x is 0.1M, then, the half life is
A.
B.
C.
D. none of these
Answer : Option C
Explaination / Solution:




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Q.3
The correct difference between first and second order reactions is that
A. A first order reaction can be catalysed; a second order reaction cannot be catalysed.
B. The half life of a first order reaction does not depend on [A0]; the half life of a second order reaction does depend on [A0].
C. The rate of a first order reaction does not depend on reactant concentrations; the rate of a second order reaction does depend on reactant concentrations.
D. The rate of a first order reaction does depend on reactant concentrations; the rate of a second order reaction does not depend on reactant concentrations.
Answer : Option B
Explaination / Solution:

For a first order reaction

t1/2 = 0.6932/k

For a second order reaction




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Q.4
In a solid atom M occupies ccp lattice and (1/3) of tetrahedral voids are occupied by atom N. find the formula of solid formed by M and N.
A. MN
B. M3N
C. MN3
D. M3N2
Answer : Option D
Explaination / Solution:

if the total number of M atoms is n, then the number of tetrahedral voids

 =2n

given that (1/3)rd of tetrahedral voids are occupied i.e., (1/3)x2n are occupied i.e., by N atoms

M:N n : (2/3) n

1 : (2/3)

3 : 2 M3 N2


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Q.5
If ‘a’ is the length of the side of the cube, the distance between the body centered atom and one corner atom in the cube will be
A.
B.
C.
D.
Answer : Option D
Explaination / Solution:

if a is the length of the side, then the length of the leading diagonal passing through the body centered atom is √3a

Required distance (√3/2) a


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Q.6
Oxidation state of Iron and the charge on the ligand NO in [ Fe ( H2O)5 NO] SO4 are
A. +2 and 0 respectively
B. +3 and 0 respectively
C. +3 and -1 respectively
D. +1 and +1 respectively
Answer : Option D
Explaination / Solution:



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Q.7
Which kind of isomerism is possible for a complex [Co ( NH3)4 Br2] Cl ?
A. geometrical and ionization
B. geometrical and optical
C. optical and ionization
D. geometrical only
Answer : Option A
Explaination / Solution:

For [ MA4 B2 ]n+ complexes-geometrical isomerism is possible



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Q.8
Which one of the following ions has the same number of unpaired electrons as present in V3+?
A. Ti3+
B. Fe3+
C. Ni2+
D. Cr3+
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.9
A white crystalline salt (A) react with dilute HCl to liberate a suffocating gas (B) and also forms a yellow precipitate . The gas (B) turns potassium dichromate acidified with dil H2SO4 to a green coloured solution(C). A,B and C are respectively
A. Na2SO3 , SO2 , Cr2 ( SO4)3
B. Na2 S2O3 , SO2 , Cr2 ( SO4 )3
C. Na2 S , SO2 , Cr2 ( SO4 )3
D. Na2 SO4 , SO2 , Cr2 ( SO4)3
Answer : Option A
Explaination / Solution:




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Q.10
The actinoid elements which show the highest oxidation state of +7 are
A. Np, Pu ,Am
B. U, Fm, Th
C. U, Th, Md
D. Es, No, Lr
Answer : Option A
Explaination / Solution:
No Explaination.


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