When sugar 'X' is boiled with dilute H₂SO₄ in alcoholic solution, two isomers 'A' and 'B' are formed. 'A' on oxidation with HNO₃ yields saccharic acid where as 'B' is laevorotatory. The compound 'X' is :

For combustion of one mole of magnesium in an open container at 300 K and 1 bar pressure, $$\Delta$$_CH^{$$\Theta $$} = $$-$$601.70 kJ mol^$$-$$1, the magnitude of change in internal energy for the reaction is __________ kJ. (Nearest integer)

(Given : R = 8.3 J K^$$-$$1 mol^$$-$$1)

2.5 g of protein containing only glycine (C₂H₅NO₂) is dissolved in water to make 500 mL of solution. The osmotic pressure of this solution at 300 K is found to be 5.03 $$\times$$ 10^$$-$$3 bar. The total number of glycine units present in the protein is ____________.

(Given : R = 0.083 L bar K^$$-$$1 mol^$$-$$1)

For the given reactions

Sn²⁺ + 2e^$$-$$ $$\to$$ Sn

Sn⁴⁺ + 4e^$$-$$ $$\to$$ Sn

the electrode potentials are ; $$E_{S{n^{2 + }}/Sn}^o = - 0.140$$ V and $$E_{S{n^{4 + }}/Sn}^o = + 0.010$$ V. The magnitude of standard electrode potential for $$S{n^{4 + }}/S{n^{2 + }}$$ i.e. $$E_{S{n^{4 + }}/S{n^{2 + }}}^o$$ is _____________ $$\times$$ 10^$$-$$2 V. (Nearest integer)