Write the main structural difference between DNA and RNA. Of the four bases, name those which are common to both DNA and RNA.

Complete the following chemical equations :
(i)

(ii)

OR

State reasons for the following :
(i) Cu (I) ion is not stable in an aqueous solution.
(ii)Unlike Cr³⁺, Mn²⁺, Fe³⁺ and the subsequent other M²⁺ ions of the 3d series of elements, the 4d and the 5d series metals generally do not form stable cationic species.

Explain what is meant by the following:

(i) Peptide linkage

(ii) Pyranose structure of glucose

A solution prepared by dissolving 8.95 mg of a gene fragment in 35.0 mL of water has an osmotic pressure of 0.335 torr at 25°C. Assuming that the gene fragment is a non-electrolyte, calculate its molar mass.

Classify colloids where the dispersion medium is water. State their characteristics and write an example of each of these classes.

OR

Explain what is observed when

(i) an electric current is passed through a soln.

(ii) a beam of light is passed through a soln.

(iii) an electrolyte (say NaCl) is added to ferric hydroxide sol.