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

Write the important structural differences between DNA and RNA.

An organic compound (A) with molecular formula C₂Cl₃O₂H is obtained when (B) reacts with Red P and Cl₂. The organic compound (B) can be obtained on the reaction of methyl magnesium chloride with dry ice followed by acid hydrolysis.

1. Identify A and B.
2. Write down the reaction for the formation of A from B. What is this reaction called?
3. Give any one method by which organic compound B can be prepared from its corresponding acid chloride.
4. Which will be the more acidic compound (A) or (B)? Why?
5. Write down the reaction to prepare methane from the compound (B).

Write two differences between DNA and RNA.

Mention two important functions of nucleic acids.

Give a reason for the following observations:

The two strands in DNA are complementary to each other.

Assertion (A): The backbone of DNA and RNA molecules is a chain consisting of heterocyclic base, pentose sugar and phosphate group.

Reason (R): Nucleotides and nucleosides mainly differ from each other in the presence of phosphate group.

Silver crystallises in F.C.C. (face-centred cubic crystal) structure. The edge length of the unit cell is found to be 408.7 pm. Calculate density of the unit cell.

[Given: Molar mass of silver is 108 g mol^-1 ]

What happens when 

(i) PCl₅ is heated ? Write the reactions involved.

Account for the following : Cl – CH₂COOH is a stronger acid than CH₃COOH.

What products would be formed when a nucleotide from DNA containing thymine is hydrolysed?

What are the different types of RNA found in the cell?

Write the important functional differences between DNA and RNA.

Give the reason for bleaching action of Cl₂.

Name two poisonous gases which can be prepared from chlorine gas.

How can you prepare Cl₂ from HCl ? Write reaction only.

Write balanced equations for chlorine gas is passed into a solution of NaI in water.

Determine the density of Cesium chloride which crys tallizes in BCC type structure with the edge length 412.1 pm. The atomic masses of Cs and Cl are 133 and 35.5 respectively.

What type of linkage is responsible for the formation of proteins?

Write the product formed when glucose is treated with HI ?

Which type of solid conduct electricity in molten state but not in solid state?