For the reaction A $$\to$$ B, the rate constant k(in s^$$-$$1) is given by

$${\log _{10}}k = 20.35 - {{(2.47 \times {{10}^3})} \over T}$$

The energy of activation in kJ mol^$$-$$1 is ____________. (Nearest integer) [Given : R = 8.314 J K^$$-$$1 mol^$$-$$1]

Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is ______________ $$\times$$ 10^$$-$$1 M. (Nearest integer) [Atomic mass : Na = 23.0, O = 16.0, H = 1.0]

According to molecular orbital theory, the number of unpaired electron(s) in $$O_2^{2 - }$$ is :

The transformation occurring in Duma's method is given below :

$${C_2}{H_7}N + \left( {2x + {y \over 2}} \right)CuO \to xC{O_2} + {y \over 2}{H_2}O + {z \over 2}{N_2} + \left( {2x + {y \over 2}} \right)Cu$$

The value of y is ______________. (Integer answer)