I think the correct answer would be the third option. The reason I2 has a higher melting point than F2 is because I2 possesses a more polarizable electron cloud. I2 contains more electrons than F2 which would result to a stronger intermolecular forces. Having stronger intermoleculer forces would mean more energy is needed to break the bonds so a higher melting point would be observed.
The answer is A, because of the chemical reaction taking place color can change (as in this case). Hope it helps!
The balanced chemical reaction is:
2HCl + Ca = CaCl2 + H2
We are given the amount of the reactants to be used for the reaction. These values will be the starting point of our calculations.
100 g HCl ( 1 mol HCl / 36.46 g HCl ) = 2.74 mol HCl
100 g Ca ( 1 mol Ca / 40.08 g ) = 2.08 mol Ca
From the reaction, the mole ratio of the reactants is 2:1 where every 2 moles of hydrochloric acid, 1 mole of calcium is required. Therefore, the limiting reactant for this case is calcium.
Answer: The overall equation will be 
Explanation:
The representation is given by writing the anode on left hand side followed by its ion with its molar concentration. It is followed by a salt bridge. Then the cathodic ion with its molar concentration is written and then the cathode.
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation state of the substance increases.
Anode : 
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation state of the substance gets reduced.
Cathode : 
The number of electrons lost must be equal to the number of electrons gained , thus overall equation will be :
