Question

The oxidation number of chlorine in HOCl is:
A ) -1
B ) zero
C ) +1
D ) +2

Answer 1

Hint: Oxidation State is the total number of electrons either gained or lost by an atom to form a chemical bond with another atom.The sum of the oxidation states of all the atoms for a neutral compound.

Complete step by step answer:
Oxidation state is also known as the oxidation number. It is the total number of electrons either gained or lost by an atom to form a chemical bond with another atom.
chlorine usually forms compounds in which it has oxidation states ranging from-1 to +7. Thus, in compounds such as sodium chloride and hydrogen chloride, the oxidation state of chlorine is -1 as it gains 1 electron during compound formation. On the other hand, in compounds such as \[{\rm{C}}{{\rm{l}}_2}{{\rm{O}}_7}{\rm{ and KCl}}{{\rm{O}}_4}\], the oxidation state of chlorine is +7.

Let X be the oxidation state of chlorine in HOCl. The oxidation states of hydrogen and oxygen are +1 and -2 respectively. In a neutral molecule, the sum of the oxidation states of all the atoms / ions is zero.
Calculate the oxidation state of chlorine in HOCl.
\[\begin{array}{c}
 + 1 - 2 + X = 0\\
X - 1 = 0\\
X = + 1
\end{array}\]

Hence, the oxidation state of chlorine in HOCl is +1.

The correct answer is option C )

Note:
Do not include wrong values for the oxidation state of hydrogen and oxygen in the calculation for the oxidation state of chlorine. OS of hydrogen and oxygen are 1 and 2 respectively. The OS of oxygen varies for peroxide.