A solution containing 62 g ethylene glycol in 250 g water is cooled to $$-$$ 10^oC. If K_f for water is 1.86 K kg mol^$$-$$1 , the amount of water (in g) separated as ice is :

The transition element that has lowest enthalpy of atomisation, is :

When the first electron gain enthalpy $$\left( {{\Delta _{eg}}H} \right)$$ of oxygen is $$-$$ 141 kJ/mol, its second electron gain enthalpy is :

In which of the following process, the bond order has increased and paramagnetic character has charged to diamagnetic ?