Which is not the correct statement about RNA and DNA?

120.    Which is not the correct statement about RNA and DNA?

(A) DNA is active in virus where RNA never appears in virus

(B) DNA exists as dimer while RNA is usually single stranded

(C) DNA contains deoxyribose as its sugar and RNA contains ribose

(D) RNA contains uracil in place of thymine (found in DNA) as a base

Answer:: (A)

121.    Which cycloalkane has the lowest heat of combustion per CH2 group?

(A) cyclopropane

(B) cyclobutanc

(C) cyclopontane

(D) cyclohexane

Answer:: (D)

122.    When a mixture of calcium benzoate and calcium acetate is dry distilled, the resulting compound is

(A) acetophenone

(B) benzaldehyde

(C) benzophenone

(D) acetaldehyde

Answer:: (A)

123.    What is the nature of glucose-glucose linkage in starch that makes its so susceptible to acid hydrolysis?

(A) Starch is hemiacetal

(B) Starch is acetal

(C) Starch is polymer

(D) Starch contains only few molecules of glucose

Answer:: (B)

124.    A white crystalline salt A reacts with dilute HCI to liberate a suffocating gas B and also forms a yellow precipitate. The gas B turns potassium dichromate acidified with dilute H2SO4 to a green coloured solution C. A, B and C are respectively ______.

(A) Na2S2O3, SO2, Cr2 (SO4)3

(B) Na2SO3, SO2, Cr2 (SO4)3

(C) Na2SO4, SO2, Cr2 (SO4)3

(D) Na2S, SO, Cr2 (SO4)3

Answer:: (A)

125.    According to Bayer's strain theory which is highly stable?

(A) cyclohexane

(B) cycloheptane

(C) cyclopentane

(D) cyclobutane

Answer:: (C)

126.    Acidified K2Cr2O7 solution turns green when Na2SO3 is added to it. This is due to the formation of

(A) CrSO4

(B) Cr2(SO4)3

(C)

(D) Cr2(SO3)3

Answer:: (B)