Answer is (b)
2,3,1 is the stoichiometry
The values in front of the elements are the stoichiometric values
(Since Al2Br6 has no value in front, it's considered 1)
3K + AlCl3 --------> 3 KCl + Al
element compound compound element
This is single replacement (displacement) reaction.
Answer: (1)CaSO4 -> (2)O2 + (1)CaS
Explanation: edge 2020 chem