Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions

What are nucleic acids?

How will you bring about the following conversion in not more than two steps?

Benzoic acid to Benzaldehyde

Describe the following:

Decarboxylation

Sea is the greatest source of some halogens. Comment.

Write the reactions involved Decarboxylation reaction

Give reasons for the following:

Electron gain enthalpies of halogens are largely negative.

Out of chlorobenzene and benzyl chloride, which one gets easily hydrolysed by aqueous NaOH and why?

Write the structure of the product when chlorobenzene is treated with methyl chloride in the presence of sodium metal and dry ether.

Write the structure of the alkene formed by dehydrohalogenation of 1-Bromo-1methylcyclohexane with alcoholic KOH.

Name the base that is found in nucleotide of RNA only.

Write balanced chemical equations involved in the following reactions:
Chlorine gas reacts with cold and dilute NaOH 

Give a reason for the following : 
N-N bond is weaker than the P-P bond.

For electron affinity of halogens which of the following is correct?

The presence or absence of hydroxyl group on which carbon atom of sugar differentiates RNA and DNA?

Which one of them is not a protein?

In both DNA and RNA, heterocyclic base and phosphate ester linkages are at ____________.

Which base is present in RNA, but not in DNA?

Which of the following represents correct order of conductivity in solids?

Which of the following statements are true about metals?

(i) Valence band overlaps with conduction band.

(ii) The gap between valence band and conduction band is negligible.

(iii) The gap between valence band and conduction band cannot be determined.

(iv) Valence band may remain partially filled.

Assertion: Graphite is a good conductor of electricity however diamond belongs to the category of insulators.
Reason: Graphite is soft in nature on the other hand diamond is very hard and brittle.