n-factor (also called reacting power) is the number of moles of H⁺ (for acids), OH⁻ (for bases), or total positive charge (for salts) that 1 mole of the substance provides or consumes in a reaction. It determines the equivalent weight: Eq.Wt = Molecular Weight / n-factor.

Why does HCl have n=1?

HCl is a monoprotic acid — each HCl molecule can donate exactly 1 H⁺ ion in solution: HCl → H⁺ + Cl⁻.

Why does Na₂CO₃ have n=2?

Na₂CO₃ dissociates into 2 Na⁺ and CO₃²⁻. The CO₃²⁻ accepts 2 H⁺ to form H₂CO₃ (which decomposes into H₂O + CO₂). Since it accepts 2 H⁺, its n-factor = 2.

Can an element have multiple n-factors?

Yes! For example, H₃PO₃ has n=2 (not 3) because only 2 of its 3 H atoms are replaceable by a base. H₃PO₄ has n=3. The n-factor depends on the specific reaction.

PhysicalEasyNEET: 1-2 Q3D

Chemistry lab

N-Factor Explorer — What Is Reacting Power?

Stoichiometry & Mole Concept

Explore the interactive model.

Loading lab

Molecule select karo, phir + daba ke H⁺ add karo — scale tabhi balance hoga jab H⁺ count = n-factor

How to use this lab

1H⁺ add (+) karke reacting power yaani n-factor find karo.
2Balance scale se equivalents ka idea pakdo.
3Alag acids/bases try karke n-factor compare karo.

About this lab

Pour H⁺ ions onto the right pan of a 3D balance scale and see how many it takes to match one molecule's reacting power. Discover that n-factor = number of H⁺ a molecule gives or takes.

What you're seeing

n-factor (reacting power) batata hai ki 1 mole of substance kitne moles of H⁺ ions ke saath react karta hai. Acids ke liye, n-factor = replaceable H⁺ ions ki sankhya. Bases ke liye, n-factor = replaceable OH⁻ groups ki sankhya. Salts ke liye, n-factor = total positive charge.

Key NEET facts

Monoprotic Acids: n = 1
HCl, HNO₃, CH₃COOH — each gives 1 H⁺ per molecule.
Diprotic Acids: n = 2
H₂SO₄, H₂CO₃, H₂C₂O₄ — each gives 2 H⁺ per molecule.
Triprotic Acids: n = 3
H₃PO₄ gives 3 H⁺ per molecule.
Bases & Salts: n = OH⁻ count or cation charge
NaOH: n=1, Ca(OH)₂: n=2, Na₂CO₃: n=2 (2 Na⁺ = 2 charge).

Memory trick

n-factor = reacting power. Acid ka n = H⁺ jo de sakta hai. Base ka n = OH⁻ jo de sakta hai. Salt ka n = cation ka total charge.

Practice

Test Yourself

What is the n-factor of H₂SO₄?

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Atomic Mass Unit — How Heavy Is One Atom?

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