Question

Q13. Explain what is wrong with this double displacement reaction?
NaCl(aq) + KBr(aq) → NaK(aq) + CIBr(aq)

Answer 1

Since this is an aqueous medium, both compounds will dissociate. If we consider the dissociation of each individual compound:

NaCl → Na⁺ + Cl⁻

KBr →  K⁺ + Br⁻

Cations should pair with anions .

Here, Na⁺ and  K⁺both are cations and Cl⁻ and Br⁻ are both anions. As you know, opposite charges attract and equal charges repel. Here there is mutual repulsion between Na⁺ and  K⁺ & Cl⁻ and Br⁻. So, they have tendency to form bonds with the oppositely charged atom.

Hence, correct equation is :

NaCl + KBr →  NaBr + KCl

Answer 2

THE EQUATION IS ABSOLUTELY WRONG IT HAS TO BE

Nacl+KBr--》NaBr+KCl

ACCORDING TO THE STATEMENT FOR DOUBLE DISPLACEMENT REACTION IT SAYS DURING SUCH REACTION A LESS REACTIVE METAL DISPLACES A HIGHER REACTIVE METAL IN ITS AQUEOUS SOLUTION.

BUT HERE IN THE PRODUCTS SIDE YOU HAVE DIRECTLY WRITTEN THAT A METAL IS REACTING WITH ANOTHER METAL WHICH IS PRACTICALLY IMPOSSIBLE SO IT ACTUALL HAS TO COME IN THE PLACE OF ANOTHER METAL BUT NOT NON METAL.

AND ANOTHER REASON A METAL WITH SAME CHARGE CANNOT FORM A BOND WITH EACH OTHER BUT ONLY OPPOSITE CHARGES CAN MAKE A BOND.

HERE SODIUM AND POTTASIUM HAVE BOTH POSITIVE CHARGES,CHLORINE AND BROMINE HAVE BOTH NEGATIVE CHARGE.