Question

Which of the following displacement reactions is expected?

1. 2 KCl + Hg → HgCl2 + 2 K
2. 2 KCl + Hg → K2Hg + Cl2
3. 2KF+Cl2 →2KCl+F2
4.2KCl+F2 →2KF+Cl2

Answer 1

The expected displacement reaction among the options provided is 2KCl + F2 → 2KF + Cl2. This occurs because fluorine is more reactive than chlorine and can displace it from potassium chloride to form potassium fluoride and chlorine gas. The correct option is 4.2KCl+F2 →2KF+Cl2.

Step-by-step explanation:

The question asks which of the listed displacement reactions is expected to occur. In a displacement reaction, one element replaces another in a compound, typically either a less reactive metal being replaced by a more reactive one or a halogen being replaced by a more reactive halogen. Analyzing the given options:

• 2 KCl + Hg → HgCl2 + 2 K (This will not happen because Hg cannot displace K from its salt.)
• 2 KCl + Hg → K2Hg + Cl2 (Mercury and potassium do not form a compound like K2Hg in a simple displacement reaction.)
• 2KF + Cl2 → 2KCl + F2 (This will not happen because F2 is more reactive than Cl2 and cannot be displaced by it.)
• 2KCl + F2 → 2KF + Cl2 (This is the expected reaction because fluorine, being more reactive than chlorine, can displace chlorine from potassium chloride.)

Therefore, the expected displacement reaction is 2KCl + F2 → 2KF + Cl2, which is option 4.