Some Basic Concept in Chemistry Formula MCQ - Practice Questions with Answers

1. Enhance Your Knowledge

• Some substances like CuSO₄.5H₂O, Na₂CO₃.10H₂O have a tendency to lose water in the air. These are called efflorescent and this tendency is called efflorescence.
• Some solid substances like NaOH, KOH, which have a tendency to absorb moisture from the air and to get wet are called 'Deliquescent' and this tendency is called Deliquescence.
• Hygroscopic substances Ilke quicklime (CaO) anhydrous P₂O₅, etc., absorb moisture from the air.
• To find the equivalent weight of an acid: 

It is possible by Silver Salt Formation Method.

2. In Redox Reaction

3. In Acid-Base Titration

Z₁M₁V₁ = Z₂M₂V₂

Here Z₁ = acidity or basicity of substance - 1

and Z₂ = acidity or basicity of substance - 2

For a mixture of a solution of non-reacting substances.

N₁V₁ + N₂V₂ + N₃V₃ = N_mixV_mix

If all the three acids are monobasic or bases are monoacidic,

M₁V₁ + M₂V₂ + M₃V₃ = M_mixV_mix

If we mix HCl and H₂SO₄ then, 'M' of H₂SO₄ will be multiplied by 2 because H₂SO₄ is dibasic acid.

4. Law of equivalence is used only in the following conditions

If either a substance or solution reacts completely with a known volume of a standard solution, then 

The number of equivalents of substance = Number of equivalents of the standard solution.

Number of eq. of metal = Number of eq. of solution