(i) On heating the powder: sugar has a higher boiling point than salt. On heating, if the white powder is sugar, it will melt down to a light brown liquid form. Salt, on the other hand, will not melt.

(ii) Salt is a better conductor of electricity: The white powder is dissolved in water and conduction of electricity is checked. If the solution conducts electricity, it is a salt. This is because salt is made up of ions while sugar is made of uncharged particles.