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Karnataka Board PUCPUC Science 2nd PUC Class 12

PUC Science 2nd PUC Class 12 - Karnataka Board PUC Important Questions

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For the first order thermal decomposition reaction, the following data were obtained:

Time / sec               Totalpressure / atm

0                              0.30

300                          0.50

Calculate the rate constant

(Given: log 2 = 0.301, log3 = 0.4771, log 4 = 0.6021)

Appears in 1 question paper
Chapter: [3] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction

The rate constant of a first order reaction increases from 4 × 10−2 to 8 × 10−2 when the temperature changes from 27°C to 37°C. Calculate the energy of activation (Ea). (log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)

Appears in 1 question paper
Chapter: [3] Chemical Kinetics
Concept: Temperature Dependence of the Rate of a Reaction

A first order reaction takes 23.1 minutes for 50% completion. Calculate the time required for 75% completion of this reaction.

(log 2 = 0.301, log 3 = 0.4771, log 4 = 0.6021)

Appears in 1 question paper
Chapter: [3] Chemical Kinetics
Concept: Half Life Period of a Reaction

A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is doubled?

Appears in 1 question paper
Chapter: [3] Chemical Kinetics
Concept: Factors Influencing Rate of a Reaction

Which metal in the first transition series (3d series) exhibits + 1 oxidation state most frequently and why?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Which of the following cations are coloured in aqueous solutions and why ?

Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

How would you account for the following? 

Transition metals exhibit variable oxidation states.

 

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)
 
 
 

Complete the following chemical equations:

`(i) Cr_2O_7^(2-)+6Fe^(2+)+14H^+ ->`

`(ii) 2CrO_4^(2-)+2H^+ ->`

`(iii) 2MnO_4^-+5C_2O_4^(2-)+16H^+ ->`

 
 
 
Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Complete the following equations:

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Complete the following equations: Cr2O72- + 14H+ + 6I →

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co

Answer the following: Write the element which shows maximum number of oxidation states. Give reason.

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co

Answer the following: Which element has the highest m.p?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co

Answer the following: Which element shows only +3 oxidation state?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co

Answer the following: Which element is a strong oxidising agent in +3 oxidation state and why?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Why do the transition elements have higher enthalpies of atomisation?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Complete the following equation:

\[\ce{2MnO4- + 6H+ + 5NO2- ->}\]

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

What are the consequences of lanthanoid contraction?

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: F-block Elements >> The Lanthanoids

How would you account for the following? 

Zr (Z = 40) and Hf (Z = 72) have almost identical radii.

 

Appears in 1 question paper
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Write the formula of Tetraminodichloroplatinum (IV) chloridex.

Appears in 1 question paper
Chapter: [5] Coordination Compounds
Concept: Nomenclature of Coordination Compounds - Formulas of Mononuclear Coordination Entities
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