55) Amongst the following, the most basic compound is:

56) The concentration of an organic compound in chloroform is 6.15 gm per 100 mL of solution. A portion of this solution in a 5 cm polarimeter tube causes an observed rotation of −1.2^o. What is the specific rotation of the compound?

57) Which of the following electrophilic substitutions is reversible?

58) Ozonolysis of mesitylene gives:

59) Which of the following aromatic compounds fails to undergo Friedal−Crafts reaction?