हिंदी

Science (English Medium) कक्षा १२ - CBSE Important Questions

Advertisements
[object Object]
[object Object]
विषयों
मुख्य विषय
अध्याय

Please select a subject first

Advertisements
Advertisements
< prev  561 to 580 of 6271  next > 

What happens to the rate constant k and activation energy Ea as the temperature of a chemical reaction is increased? Justify.

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

Account for the following: 

Cr2+ is a strong reducing agent.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

When chromite ore FeCr2O4 is fused with NaOH in presence of air, a yellow-coloured compound (A) is obtained, which on acidification with dilute sulphuric acid gives a compound (B). Compound (B) on reaction with KCl forms an orange coloured crystalline compound (C).

(i) Write the formulae of the compounds (A), (B) and C.

(ii) Write one use of compound (C).

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Complete the following chemical equation

8MnO4- + 3S2O32- + H2O →

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

What are the transition elements? Write two characteristics of the transition elements.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

How would you account for the following:

Actinoid contraction is greater than lanthanoid contraction.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: F-block Elements >> The Actinoids

How would you account for the following : Transition metals form coloured compounds

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Complete the following equation :

`2MnO_4^(-)+6H^++5NO_2^(-)rarr`

 

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Account for the following:

Cu+ ion is unstable in aqueous solution.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Complete the following equations:Cr2O72- + 2OH

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Complete the following equations : MnO4- + 4H+ + 3e- →

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

With reference to structural variability and chemical reactivity, write the differences between lanthanoids and actinoids

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: F-block Elements >> The Actinoids

Name a member of the lanthanoid series which is well known to exhibit +4 oxidation state.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: F-block Elements >> The Lanthanoids

Out of Mn3+ and Cr3+, which is more paramagnetic and why ?

(Atomic nos. : Mn = 25, Cr = 24)

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Complete the following chemical equation

Cr2O72- + 3Sn2+ + 14H+

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

Explain why Cu+ ion is not stable in aqueous solutions?

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Indicate the steps in the preparation of KMnO4 from pyrolusite ore.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals

How would you account for the following? 

Transition metals and their compounds act as catalysts.

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: General Properties of the Transition Elements (d-block)

Complete the following chemical equations :

Cu + H2SO4(conc.) →

Appears in 3 question papers
Chapter: [4] d-block and f-block Elements
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
< prev  561 to 580 of 6271  next > 
Advertisements
Advertisements
CBSE Science (English Medium) कक्षा १२ Important Questions
Important Questions for CBSE Science (English Medium) कक्षा १२ Biology
Important Questions for CBSE Science (English Medium) कक्षा १२ Chemistry
Important Questions for CBSE Science (English Medium) कक्षा १२ Computer Science (C++)
Important Questions for CBSE Science (English Medium) कक्षा १२ Computer Science (Python)
Important Questions for CBSE Science (English Medium) कक्षा १२ English Core
Important Questions for CBSE Science (English Medium) कक्षा १२ English Elective - NCERT
Important Questions for CBSE Science (English Medium) कक्षा १२ Entrepreneurship
Important Questions for CBSE Science (English Medium) कक्षा १२ Geography
Important Questions for CBSE Science (English Medium) कक्षा १२ Hindi (Core)
Important Questions for CBSE Science (English Medium) कक्षा १२ Hindi (Elective)
Important Questions for CBSE Science (English Medium) कक्षा १२ History
Important Questions for CBSE Science (English Medium) कक्षा १२ Informatics Practices
Important Questions for CBSE Science (English Medium) कक्षा १२ Mathematics
Important Questions for CBSE Science (English Medium) कक्षा १२ Physical Education
Important Questions for CBSE Science (English Medium) कक्षा १२ Physics
Important Questions for CBSE Science (English Medium) कक्षा १२ Political Science
Important Questions for CBSE Science (English Medium) कक्षा १२ Psychology
Important Questions for CBSE Science (English Medium) कक्षा १२ Sociology
Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×