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14.8     When RNA is hydrolysed, there is no relationship among the quantities of different bases obtained. What does this fact suggest about the structure of RNA?

When RNA is hydrolysed, there is no relationship among the quantities of different bases obtained, this fact suggests that RNA is a single strand structure. Unlike DNA which is a double strand structure in which pairing of bases occurs (for e.g. adenine pairs with thymine). Thus, on hydrolysis, the amount of adenine produced will be the same as the amount produced by thymine. In RNA there is no...

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

When a nucleotide from the DNA containing thymine is hydrolyzed, the products are thymine β-D-2-deoxyribose and phosphoric acid. 

14.6     Why cannot vitamin C be stored in our body?

Vitamin C is a water-soluble vitamin which is excreted from the body in the form of urine and cannot be stored. So they must be supplied in the diet regularly.

14.5     Where does the water present in the egg go after boiling the egg?

Due to denaturation of proteins, globules unfold and helix gets uncoiled which changes its biological activity. In denaturation, secondary and tertiary structures are destroyed whereas primary structure remains the same. Due to this process (denaturation of proteins) coagulation of egg take place while boiling. In egg, the globular protein changes into a rubber-like structure which is...

14.4     The melting points and solubility in water of amino acids are generally higher than that of the corresponding halo acids. Explain.

Amino acids have both acidic and basic group(amine) which lead to the formation of zwitterions and make them dipolar compounds. Due to this property, they form strong molecular bonds themselves and also with water. This result high melting point and good solubility in water as compared to haloacids. Halo acids doesn't exhibit the property of dipolar compounds. Only carboxyl group of haloacid is...

14.3     How do you explain the absence of aldehyde group in the pentaacetate of D-glucose?

When pentaacetate of glucose is made to react with hydroxylamine, it does not react indicating the absence of free —CHO group. In aqueous solution, the cyclic structure (have -OH group at C-1 ) should get converted to open chain structure which has an aldehyde group at C-1. It then should react with hydroxylamine and give glucose oxime. But such case is not observed. This suggests that in...

14.2     What are the expected products of hydrolysis of lactose?

The expected product in the hydrolysis of lactose is Galactose and Glucose.         

14.1     Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.

We know that water is a polar molecule. It is also known that "like dissolves like". So either polar molecule or the compounds which can form hydrogen bonds with water molecules will get dissolved in water. Glucose and sucrose have five and eight -OH groups respectively. So they are likely to form hydrogen bonds with molecules with water. In the case of cyclohexane and benzene, these are...

11.12 (4)  Predict the products of the following reactions: 

                

 Reaction between ter-butyl ethyl ether and HI

11.12 (3) Predict the products of the following reactions: 

           

Reaction between ethoxybenzene and

 11.12 (2)  Predict the products of the following reactions:

              

The reaction between ethoxybenzene and HBr is

11.12 (1)  Predict the products of the following reactions:

                  CH_3 -CH_2 -CH_2 -O - CH_3 +HBr 

Reaction is

 11.11  Which of the following is an appropriate set of reactants for the preparation of 1-methoxy-4-nitrobenzene and why?

          

(ii) is appropriate because   is nucleophile whereas is also a strong base. So elimination will be dominating in (i).

11.10  Write the reactions of Williamson synthesis of 2-ethoxy-3-methylpentane starting from ethanol and 3-methylpentan-2-ol.

1.Reaction of ethanol with hydrogen bromide. 2. Reaction of 3-methylpentan-2-ol with sodium 3. Reaction of product formed in 1st and reaction with the product formed in the 2nd reaction.

 11.9 (2)  Write the equations involved in the following reactions:  Kolbe’s reaction

 Kolbe’s reaction

11.9 (1)  Write the equations involved in the following reactions: Reimer - Tiemann reaction

Reimer - Tiemann reaction

11.8  Ortho and para nitrophenols are more acidic than phenol. Draw the resonance structures of the corresponding phenoxide ions.

Resonance structure of ortho-nitrophenol Resonance structure of para-nitrophenol

 11.7 (2)  Predict the major product of acid catalysed dehydration of  butan-1-ol

Dehydration of  butan-1-ol But-2-ene is the major product.

11.7(1)  Predict the major product of acid catalysed dehydration of 1-methylcyclohexanol

Dehydration of 1-methylcyclohexanol 1-Methylcyclohexene is the major product.

11.6 (6) Give structures of the products you would expect when each of the following alcohol reacts with SoCl_2  with 2-Methylbutan-2-ol

Reaction of   with 2-Methylbutan-2-ol
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