Question

Which reaction occurs spontaneously?
(1) Cl2(g) + 2NaBr(aq)-->Br2(l) + 2NaCl(aq)
(2) Cl2(g) + 2NaF(aq)--> F2(g) + 2NaCl(aq)
(3) I2(s) + 2NaBr(aq)--> Br2(l) + 2NaI(aq)
(4) I2(s) + 2NaF(aq)--> F2(g) + 2NaI(aq)

Answer 1

The reaction occurs spontaneously is Cl2(g) + 2NaBr(aq)-->Br2(l) + 2NaCl(aq). The answer is number 1. The rest of teh choices do not asnwer the question above.

Answer 2

The answer is: (1) Cl2(g) + 2NaBr(aq)-->Br2(l) + 2NaCl(aq).

In this chemical reaction chlorine change oxidation number from 0 to -1 (reduction) and bromine change oxidation number from -1 to 0 (oxidation).

Chlorine is stronger oxidation reagent than bromine.

In VIIA or group 17 (halogen elements) there are six elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At) and tennessin(Ts).

They have high electronegativity because they have seven valence electrons in their outermost energy level, so they can gain an electron to have the octet rule.  

Going down in the group, element are weaker oxidazing reagent and less reactive.

Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.