Balance Any Chemical Equation in Seconds | Simple Trick for Class 10 Students

We generally use trial and error method to balance chemical equation by the following trick you can balance a chemical equation within a minute!

Here what we used to do:

In the trial and error method, we adjust the number of atoms on each side of the equation by placing suitable numbers (coefficients) before the chemical formulas until the number of atoms of each element is equal on both sides.

Let’s balance this equation using the trial and error method:

Unbalanced Equation:
Fe + H₂O → Fe₃O₄ + H₂

Step 1: Balance Fe (Iron)

On the right side, Fe₃O₄ has 3 Fe atoms, so put 3 Fe on the left side:

3Fe + H₂O → Fe₃O₄ + H₂

Step 2: Balance O (Oxygen)

Fe₃O₄ has 4 oxygen atoms, so we need 4 H₂O molecules on the left side to get 4 oxygen atoms:

3Fe + 4H₂O → Fe₃O₄ + H₂

Step 3: Balance H (Hydrogen)

On the left side, 4H₂O means 4 × 2 = 8 hydrogen atoms, so we need 4 H₂ molecules on the right side:

3Fe + 4H₂O → Fe₃O₄ + 4H₂

✅ Now the equation is balanced:

• Fe: 3 on both sides
• O: 4 on both sides
• H: 8 on both sides

Final Balanced Equation:

3Fe + 4H₂O → Fe₃O₄ + 4H₂

This is how the trial and error method works—by trying different numbers until all atoms are equal on both sides. However, when solving complex equations, you will find that balancing with this method is very difficult. 

Steps to Balance Using Variables (a, b, c, d Method) #The short trick

Step 1:  Assign coefficients (a, b, c, d, etc.) to each reactant and product.

Example: Let's balance Fe + H₂O → Fe₃O₄ + H₂
Assign variables:

aFe + bH₂O → cFe₃O₄ + dH₂

Write element-wise equations (Atom Conservation Rule)

• Iron (Fe): Since Fe₃O₄ has 3 Fe atoms, we write:

                        a=3c

• Hydrogen (H): Water has 2H, and H₂ is diatomic:

                        2b=2d

·      Oxygen (O): Water has 1 oxygen, and Fe₃O₄ has 4 oxygen:

              b=4c

Step 2: Assume one variable (usually a = 1)

o    Let’s take c = 1

o    From a = 3c, we get a = 3

o    From b = 4c, we get b = 4

o    From 2b = 2d, we get d = 4

Final balanced equation:

3Fe + 4H₂O → Fe₃O₄ + 4H₂

This method can be used for complex equations

Now Try to balance the following equations

(a) HNO₃ + Ca(OH)₂ → Ca(NO₃)₂ + H₂O
(b) NaOH + H₂SO₄ → Na₂SO₄ + H₂O
(c) NaCl + AgNO₃ → AgCl + NaNO₃
(d) BaCl₂ + H₂SO₄ → BaSO₄ + HCl