Solved Problems on Equivalent Weight

Question 1: Calculate the Equivalent weight of H₂SO₄.

Answer:

Two H+ ions are present for every mole of sulfuric acid, or n = 2. Find the total atomic masses of the S, O, and H in your formula by referencing a periodic table:

S = 32.07

O = 16.00

H = 1.01

Add the molecular weight of H₂SO₄: 

32.07 + 4(16.00) + 2(1.01) = 98.08 g/mol

Eq = 98.08 / 2 = 49.04 g/eq.

H₂SO₄ has a gram equivalent weight of 49.04 g/eq.

Question 2: Calculate the Equivalent weight of NaOH.

Answer:

Since there is just one OH-, there are only one equivalent. Find the total atomic masses of the Na, O, and H in your formula by referencing to periodic table:

Na = 22.99

O = 16.00

H = 1.01

Add the molecular weight of NaOH: 

22.99 + 16.00 + 1.01 = 40.00 g/mole

Eq = 40.00 / 1 = 40.00 g/eq

NaOH has a gram equivalent weight of 40.00 g/eq

Question 3: Calculate the Equivalent weight of HCL.

Answer:

Since there is just one H⁺, there are only one equivalent. Find the total atomic masses of Cl and H in your formula by referencing to periodic table:

Cl = 35.45

H = 1.01

Add the molecular weight of HCL:

35.45 + 1.01 = 36.46 g/mole

Eq = 36.46 / 1 = 36.46 g/eq

HCL has a gram equivalent weight of 36.46 g/eq

Question 4: Calculate the Equivalent weight of Ca(OH)₂ →Ca⁺ + 2 OH^–

Answer:

The calcium hydroxide base releases two hydroxyl ions into the environment. Its valency factor, or X value, will therefore be 2.

The calcium hydroxide base has a molecular weight of 74 g/mole.

Equivalent weight = molecular weight / valency

Equivalent weight of calcium hydroxide base= 74 / 2 = 37 g/eq

Therefore, calcium hydroxide has a equivalent weight of 37 g/eq

Question 5: Calculate the Equivalent weight of Al(OH)₃ → Al⁺3 + 3 OH^–

Answer:

The aluminum hydroxide base releases three hydroxyl ions. Its valency factor, or X value, will therefore 3.

The aluminum hydroxide base has a molecular weight of 78 g/mol.

Equivalent weight = molecular weight / valency

Equivalent weight of aluminum hydroxide base= 78 / 3 = 26 g/eq.

Therefore, aluminum hydroxide has a equivalent weight of 26 g/eq

The most commonly used phrase in chemistry is “equivalent weight,” which is also one of the fundamental concepts in physical chemistry. Equivalent weight commonly referred to as a gram equivalent is the mass of one equivalent or the mass of a particular material that will combine with or replace a specific amount of another substance. To say it another way, the mass of a substance that can displace 1.008 grams of hydrogen or 8.0 grams of oxygen or 35.5 grams of chlorine is its gram equivalent or equivalent weight. Let us study the Equivalent Weight in detail in this article.