Upon heating with Cu₂S, the reagent(s) that give copper metal is/are

In a galvanic cell, the salt bridge

A compound H₂X with molar weight of 80g is dissolved in a solvent having density of 0.4 gml^–1 . Assuming no change in volume upon dissolution, the molality of a 3.2 molar solution is

MX₂ dissociates in M²⁺ and X^- ions in an aqueous solution, with a degree of dissociation ($$\alpha$$) of 0.5. The ratio of the observed depression of freezing point of the aqueous solution to the value of the depression of freezing point in the absence of ionic dissociation is