Question

Write the balanced chemical equation for: ${\text{S + HNO}}_3\to {\mathrm{H}}_2{\mathrm{SO}}_4+{\mathrm{NO}}_2+{\mathrm{H}}_2\mathrm{O}$

Answer 1

Balanced Chemical equation

• A balanced equation involves an equal number of atoms for each element on the reactant and product side.

Chemical equation:

• When sulphur reacts with nitric acid sulphuric acid, nitrogen dioxide and water will be produced.

${\text{S(s) + HNO}}_3\text{(aq)}\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+{\mathrm{NO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Balancing Chemical Equation

• First, we will check the number of atoms of each compound on the reactant as well as the product side.
  

Element	Reactant side	Product side
$\mathrm{S}$	$1$	$1$
$\mathrm{H}$	$1$	$4$
${\mathrm{N}}_{}$	$1$	$1$
$\mathrm{O}$	$3$	$7$

• Here the number of atoms of hydrogen($\mathrm{H}$) and Oxygen($\mathrm{O}$) is not balanced.
• By balancing the number of $\mathrm{H}$ atoms the equation can be reduced to
  ${\text{S (s)+ 6HNO}}_3\text{(aq)}\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+{\mathrm{NO}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$
  

Element	Reactant side	Product side
$\mathrm{S}$	$1$	$1$
$\mathrm{H}$	$6$	$6$
${\mathrm{N}}_{}$	$6$	$1$
$\mathrm{O}$	$18$	$8$

• Balancing the number of Nitrogen and oxygen atoms by making the coefficient of ${\mathrm{NO}}_2$ 6, the equation can be further reduced to
  $\mathrm{S}\left(\mathrm{s}\right)+6{\mathrm{HNO}}_3\left(\mathrm{aq}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+6{\mathrm{NO}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$
  

Element	Reactant side	Product side
$\mathrm{S}$	$1$	$1$
$\mathrm{H}$	$6$	$6$
${\mathrm{N}}_{}$	$6$	$6$
$\mathrm{O}$	$18$	$18$

Hence the balanced equation is $\mathrm{S}\left(\mathrm{s}\right)+6{\mathrm{HNO}}_3\left(\mathrm{aq}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+6{\mathrm{NO}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$.