A, E, M and n represent atomic weight, equivalent weight, molecular weight and valency of an element. The correct relation is

Options

A. `A=Exxn`
B. `A=M//E`
C. `A=M//n`
D. `M=Axxn`

Answer

To find the correct relation among atomic weight (A), equivalent weight (E), molecular weight (M), and valency (N) of an element, we can follow these steps:

### Step 1: Understand the Definitions
- **Atomic Weight (A)**: The weight of an atom of an element.
- **Equivalent Weight (E)**: The mass of an element that combines with or displaces 1 mole of hydrogen or 8 grams of oxygen. It can be calculated using the formula:
\[ E = \frac{A}{N} \]
where N is the valency of the element.
- **Molecular Weight (M)**: The weight of a molecule, which is often a multiple of the atomic weight depending on the molecular formula.
- **Valency (N)**: The number of electrons an atom can lose, gain, or share during a chemical reaction.

### Step 2: Relate Equivalent Weight to Atomic Weight and Valency
From the definition of equivalent weight, we can rearrange the formula:
\[ E = \frac{A}{N} \implies A = E \times N \]
This shows that the atomic weight (A) is equal to the equivalent weight (E) multiplied by the valency (N).

### Step 3: Consider Molecular Weight
Molecular weight (M) is generally related to atomic weight, but it is not directly involved in the relationship with equivalent weight and valency. For a compound, molecular weight can be calculated as the sum of the atomic weights of all atoms in the molecule.

### Conclusion
The correct relation among the quantities is:
\[ A = E \times N \]
This means that the atomic weight is equal to the equivalent weight multiplied by the valency.