Question

Which of the following is not a correct chemical equation for a double displacement reaction? (2 points) a 2HNO3 + Mg(OH)2yields 2H2O + Mg(NO3)2 b H3PO4 + 3NaF yields 3HF + Na3PO4 c 2KNO2 + BaSO4yields K2SO4 + Ba(NO2)2 d 4NaBr + Co(SO3)2yields Br2SO3 + CoNa4

Answer 1

Answer:- d) $4NaBr+Co(SO_3)_2\rightarrow Br_2SO_3+CoNa_4$

Explanations:- In double displacement reactions, the ion exchange takes place means the anion the anion of first compound goes with the cation of second compound and the anion of second compound goes with the cation of first compound.

in last reaction, the first compound is NaBr and it has $Na^+$ ion and $Br^-$ .

The second compound is $Co(SO_3)_2$ and it has $Co^+^4$ ion and $SO_3^-^2$ ion .

So, as the ion exchange takes place, bromide ion goes with cobalt ion and the sulfite ion goes with sodium ion and the correct form of the equation is:

$4NaBr+Co(SO_3)_2\rightarrow 2Na_2SO_3+CoBr_4$

The equation they have shown is totally different and not correct as the two anions are placed together and two cations are placed together.

So, d is the right choice as it is not a correct double displacement reaction.