During compression of a spring the work done is 10kJ and 2kJ escaped to the surroundings as heat. The change in internal energy, $$\Delta $$U(inkJ) is :

Increasing order of reactivity of the following compounds for S_N1 substitution is:

HF has highest boiling point among hydrogen halides, because it has :

What would be the molality of 20% (mass/ mass) aqueous solution of KI?
(molar mass of KI = 166 g mol^–1)