Solid sample of a compound and a liquid sample of the same compound are each tested for electrical conductivity which test conclusion in the case of the compound is ionic

Ionic compounds are compound formed after a result of ionic bond which involves transfer electrons between atoms where one atom gains electrons and the other looses electrons. ionic compound only conducts electricity in liquid form (when dissolved in water or melted) when their ions are free to move. in solid state the compounds can not conduct since the ions are not free to move. therefore, the answer is (4) the solid is a poor conductor while the liquid is a good conductor.

The phase where ice changes directly to gas is called sublimation 

Well you can immediately rule out a and d because if a metal were to lose or gain protons, then it would become a different element all together. the answer here is b because the positive symbol with a number refers to how many electrons the metal can give away to become stable.