Which of the following statement is true with respect to $\mathrm{H}_2 \mathrm{O}, \mathrm{NH}_3$ and $\mathrm{CH}_4$ ?

A. The central atoms of all the molecules are $\mathrm{sp}^3$ hybridized.

B. The $\mathrm{H}-\mathrm{O}-\mathrm{H}, \mathrm{H}-\mathrm{N}-\mathrm{H}$ and $\mathrm{H}-\mathrm{C}-\mathrm{H}$ angles in the above molecules are $104.5^{\circ}, 107.5^{\circ}$ and $109.5^{\circ}$, respectively.

C. The increasing order of dipole moment is $\mathrm{CH}_4<\mathrm{NH}_3<\mathrm{H}_2 \mathrm{O}$.

D. Both $\mathrm{H}_2 \mathrm{O}$ and $\mathrm{NH}_3$ are Lewis acids and $\mathrm{CH}_4$ is a Lewis base.

E. A solution of $\mathrm{NH}_3$ in $\mathrm{H}_2 \mathrm{O}$ is basic. In this solution $\mathrm{NH}_3$ and $\mathrm{H}_2 \mathrm{O}$ act as Lowry-Bronsted acid and base respectively.

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Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boiling point of water. Choose the correct option.

Which of the following arrangements with respect to their reactivity in nucleophilic addition reaction is correct?

The carbohydrate "Ribose" present in DNA, is

A. A pentose sugar

B. present in pyranose from

C. in "D" configuration

D. a reducing sugar, when free

E. in $\propto$-anomeric form

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