The reaction, MgO(s) + C(s) $$ \to $$ Mg(s) + CO(g), for which $$\Delta $$_rH^o + 491.1 kJ mol^–1 and $$\Delta $$_rS^o = 198.0 JK^–1 mol^–1, is not feasible at 298 K. Temperature above which reaciton will be feasible is :

K₂Hgl₄ is 40% ionised in aqueous solution. The value of its van't Hoff factor (i) is:

The correct option with respect to the Pauling electronegativity values of the element is :

Let x, y be positive real numbers and m, n positive integers. The maximum value of the expression $${{{x^m}{y^n}} \over {\left( {1 + {x^{2m}}} \right)\left( {1 + {y^{2n}}} \right)}}$$ is :