Question

Balance the following reaction.

$HN{O}_3+HCl\to NO+C{l}_2+H_{2}O$

• A. $2HN{O}_3+6HCl\to 2NO+3C{l}_2+4H_{2}O$
• B. $2HN{O}_3+6HCl\to 2NO+9C{l}_2+8H_{2}O$
• C. $2HN{O}_3+26HCl\to 2NO+6C{l}_2+4H_{2}O$
• D. None of these

Answer 1

The correct option is A $2HN{O}_3+6HCl\to 2NO+3C{l}_2+4H_{2}O$

The unbalanced redox equation is as follows:
$HN{O}_3+HCl\to NO+C{l}_2+H_{2}O$
Balance all atoms other than H and O.
$HN{O}_3+2HCl\to NO+C{l}_2+H_{2}O$
The oxidation number of N changes from 5 to 2. The change in the oxidation number of N is 3.
The oxidation number of Cl changes from -1 to 0. The change in the oxidation number of one Cl atom is 1.
For two Cl atoms, the oxidation number changes by 2.
The increase in the oxidation number is balanced with decrease in the oxidation number by multiplying
$HN{O}_3$ and $NO$ with 2 and by multiplying
$HCl$ and $C{l}_2$ with 3.
$2HN{O}_3+6HCl\to 2NO+3C{l}_2+H_{2}O$
O atoms are balanced by adding 3 water molecules on RHS.
$2HN{O}_3+6HCl\to 2NO+3C{l}_2+4H_{2}O$
Hydrogen atoms are balanced. This is the balanced chemical equation.