Question

What happens when (Give chemical equations only): (i) Iodine reacts with nitric acid solution?
(ii) Chlorine reacts with sulphur dioxide?
(iii) Chlorine reacts with hot and conc. NaOH solution?
(iv) Chlorine reacts with fluorine?
(v) Zinc reacts with dil. nitric acid?

Hint:

Chlorine often shows disproportionation reactions with alkalis, while nitric acid oxidises both iodine and zinc.

Answer 1

(i) Iodine with HNO\(_3\).
Nitric acid oxidises iodine to iodic acid: \[ I_2 + 10HNO_3 \rightarrow 2HIO_3 + 10NO_2 + 4H_2O \] (ii) Chlorine with SO\(_2\).
Chlorine oxidises SO\(_2\) to H\(_2\)SO\(_4\): \[ Cl_2 + SO_2 + 2H_2O \rightarrow H_2SO_4 + 2HCl \] (iii) Chlorine with hot conc. NaOH.
Disproportionation reaction: \[ 3Cl_2 + 6NaOH \, (hot, conc.) \rightarrow 5NaCl + NaClO_3 + 3H_2O \] (iv) Chlorine with fluorine.
Formation of chlorine trifluoride: \[ Cl_2 + 3F_2 \rightarrow 2ClF_3 \] (v) Zinc with dilute nitric acid.
Zinc gives zinc nitrate and nitrogen dioxide gas: \[ Zn + 4HNO_3 \, (dil.) \rightarrow Zn(NO_3)_2 + 2NO_2 + 2H_2O \]