Question

• Write the balanced chemical equation for the following.

Potassium bromide on treatment with manganese dioxide and sulphuric acid gives manganese and potassium sulphate, bromine and water.

Answer 1

• When Potassium bromide react with manganese dioxide and sulphuric acid gives manganese sulphate, Potassium sulphate, Bromine and water.
• Potassium bromide+ Manganese dioxide + Sulphuric acid $\to$Manganese sulphate + Potassium sulphate+ Bromine+ water.

Step 1

Write the skeletal equation.

$\mathrm{KBr}+{\mathrm{MnO}}_2+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{MnSO}}_4+{\mathrm{K}}_2{\mathrm{SO}}_4+{\mathrm{Br}}_2+{\mathrm{H}}_2\mathrm{O}$

Step 2

• To equalize Bromine, multiply KBr by 2

$2\mathrm{KBr}+{\mathrm{MnO}}_2+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{MnSO}}_4+{\mathrm{K}}_2{\mathrm{SO}}_4+{\mathrm{Br}}_2+{\mathrm{H}}_2\mathrm{O}$

• To equalize Oxygen, multiply H₂SO₄ by 2

$2\mathrm{KBr}+{\mathrm{MnO}}_2+2{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{MnSO}}_4+{\mathrm{K}}_2{\mathrm{SO}}_4+{\mathrm{Br}}_2+{\mathrm{H}}_2\mathrm{O}$

• To equalize Hydrogen, multiply H₂O by 2

$2\mathrm{KBr}\left(\mathrm{aq}\right)+{\mathrm{MnO}}_2\left(\mathrm{s}\right)+2{\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\to {\mathrm{MnSO}}_4\left(\mathrm{s}\right)+{\mathrm{K}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)+{\mathrm{Br}}_2\left(\mathrm{g}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$

Thus equation is balanced.