# Equivalent weight And It’s Calculation

The **equivalent weight** is defined as the weight (or mass) of a substance that contains a hydrogen** ion**(H+) or a **hydroxide ion** (−OH−). **Acids** are proton donors, while **bases** are proton acceptors. **Gram equivalent** weight is defined as the mass in grams numerically, which is equal to Equivalent Weight.

The equivalent weight of elements having more than one valencies is variable. Like Sulphur has 2, 4, 6 as valencies. So the equivalent weight of Sulphur will also be different for different valencies.** ‘Equivalent weight’ **allows us to give it a thought on the fact that **atoms combine to form molecules** in fixed number ratios rather than **mass ratios**.

Suppose the mass of a chemical entifactor is ‘g’ grams, then the given mass contains gram equivalents given by ‘*valency*__ __*factor*__× __*moles’*.

*Equivalent* *weight is given as moles *__×__* valency*__ __*factor.*

One mole of any substance is equal to** 6.02 × 1023 (atoms or molecules)** of that substance.

The general number of equivalents formula is

**Euivalent=Molecular weight/charge number**

Where charge number is the number of proton or hydroxide ions which the compound contains.

**Equivalents of some Acids and bases are as follows**

** **A **gram equivalent** (geq) is the weight of the substance in grams divided by its equivalent weight. It can also be articulated as the number of charge elements contained times the number of moles n.

**The molecular weight of H2SO4 **

** **Molar mass of H2SO4 =

**98.07848 g/mol**

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**Equivalent weight of HCl**

H = 1 g and CL = 35.5g

HCL = 1 + 35.5 = 36.5g

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**Equivalent weight of KMnO4**

K = 39+ Mn 55 + O 4 (16X4) 64 =158 Mol wt

Eq. Wt may be 158/5 in acidic medium =31.2

In alkaline medium 158/3 = 52.7

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**Equivalent weight of Na2So3**

Equivalent weight = molecule weight/n-factor = Molecular weight/2

This way , equivalent of Na₂CO₃ = 106/2 = 53

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**Equivalent weight of Sodium Thiosulphate**

Molar mass of sodium thiosulfate=174.12

Equivalent weight of a salt is = molar mass /charge on positive ion=174.12/1=174.12

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**Equivalent mass of oxalic acid**

The Formula of oxalic acid is H2C2O4.2H2O.

Therefore, the equivalent weight of the acid is

molecular weight (126 g/mol) divided by n-factor (which is the valency=2)

Therefore, 126/2 = 63.

The equivalent weight or mass of oxalic acid is 63

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**Equivalent weight of acetic acid**

The molecular weight of CH3COOH=60.05g/mol, C has a weight of

12.01(×2)=24.02gram, and H has a wt of 1.01(×4)=4.04grams And O has a wt of 16(×2)=32g grams; 24.02+4.04+32=28.06+ 32=60.06 grams .

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**Equivalent weight of CaCO3**

The total mass of CaCO3=40g+12g+48g=100g

Then, the equivalent mass of CaCO3 is 100g/2=50g.

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**Equivalent weight of oxygen**

Molecular mass of O2 = 32; Valency = 2

Eq. weight = 32/2 = 16

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**Equivalent weight of EDTA (****Disodium**)

**Disodium**)

Chemical Formula [(HO2CCH2-)(NaO2CCH2-)N-CH2]2·2H2O

Formula Weight 372.24

Equivalent Weight 186.12 (Molar = 2 Normal)

**Equivalent weight of Sodium Chloride**

Equivalent weight=gram formula mass/valency molecular weight =58.5 so, 58.5/1 =58.5 equivalent weight of nacl=58.5.

**Equivalent weight of Sodium Carbonate**

Equivalent weight = molecule weight/n-factor = Molecular weight/2

This way, equivalent of Na₂CO₃ = 106/2 = 53

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**Molecular weight of Silver**

Molecular Weight: **107.868 g/mol**

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**Equivalent weight of Copper**

The equivalent weight of copper is **31.8 g**/eq

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**Equivalent weight of CuSO4**

equivalent mass of CuSO4 as 159.609/2 = **79.804 gm**/mol.

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**Equivalent weight of KMnO4**

Molar mass of KMnO4=158.04 g/mol

Equivalent weight of KMnO4 = 158.04/5 = 31.61 grams/equivalent

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**Molecular weight of Acetanilide**

Molecular Formula: C8H9NO

Molecular Weight: 135.16 g/mol

**Equivalent weight of H3PO4**

The molecular weight of **phosphoric acid** is; (3+31+16*4)gram/mol = 98 gram/mol. Now EQUIVALENT WEIGHT = 98/3 gram/equivalent = 32.67 gram/equivalents.

**Equivalent weight of AgNO3**

**AgNO3** – Mol. **mass** = 108 + 14 + 48 = 170g/mole !!! **Equivalent weight** = molar **wt**. / n- factor !!! and n factor for **AgNO3** is 1 !!! so its Equivalent **weight** =170g/**equivalent.**