The total number of compounds having at least one bridging oxo group among the molecules given below is _________.

$${N_2}{O_3},{N_2}{O_5},$$ $${P_4}{O_6},{P_4}{O_7},$$ $${H_4}{P_2}{O_5},{H_5}{P_3}{O_{10}},$$ $${H_2}{S_2}{O_3},{H_2}{S_2}{O_5}$$

In the following reaction sequence, the amount of $$D$$ (in g) formed from $$10$$ moles of acetophenone is ___________.

(Atomic weights in $$g\,mo{l^{ - 1}}:H = 1,C = 12,$$ $$N = 14,O = 16,$$ $$Br = 80.$$. The yield (%) corresponding to the product in each step is given in the parenthesis)

The Fischer presentation of $$D$$-glucose is given below.


The correct structure(s) of $$\beta $$-$$L$$-glucopyranose is (are) :

Consider an electrochemical cell :

$$A\left( s \right)\left| {{A^{n + }}\left( {aq,2M} \right)} \right|{B^{2n + }}\left( {aq,1M} \right)\left| {B\left( s \right).} \right.$$

The value of $$\Delta {H^ \circ }$$ for the cell reaction is twice that of $$\Delta {G^ \circ }$$ at $$300$$ $$K.$$ If the $$emf$$ of the cell is zero, the $$\Delta {S^ \circ }$$ (in $$J\,{K^{ - 1}}mo{l^{ - 1}}$$) of the cell reaction per mole of $$B$$ formed at $$300$$ $$K$$ is ___________.

(Given: $$\ln \left( 2 \right) = 0.7,R$$ (universal gas constant) $$ = 8.3J\,{K^{ - 1}}\,mo{l^{ - 1}}.$$ $$H,S$$ and $$G$$ are enthalpy, entropy and Gibbs energy, respectively.)