Question

Among the following reactions, used in titrations, select the reaction(s) in

which the chlorine is oxidised:

1. $Mn{O}_2+4HCl\to MnC{l}_2+C{l}_2+2H_{2}O$

2. $2KI+2C{l}_2\to 2KCl+I_2$
3. $CaOC{l}_2+H_{2}O\to Ca(OH{)}_2+C{l}_2$
4. $Cr{O}_{2}C{l}_2+2NaOH\to N{a}_{2}Cr{O}_4+2HCl$.

• A. Reactions $2,3$ and $4$
• B. Reaction $1$ only
• C. Reaction $1$ and $3$
• D. Reaction $4$ only
• E. Reaction $2$ and $4$

Answer 1

The correct option is A Reactions $2,3$ and $4$

Increase in oxidation state represent the oxidation.
$2KI+2C{l}_2\to 2KCl+I_2$ oxidation state of chlorine is increased from -1 to 0)
$CaOC{l}_2+H_{2}O\to Ca(OH{)}_2+C{l}_2$ oxidation state of chlorine is increased from -1 to 0)
$Cr{O}_{2}C{l}_2+2NaOH\to N{a}_{2}Cr{O}_4+2HCl$. oxidation state of chlorine is increased from -1 to 0)
Are the reaction in which the chlorine is oxidised.
Hence option A is correct.