A metal M of equivalent mass E forms an oxide of molecular formula MxOy
. The atomic mass of the metal is given by the correct equation.
A) 2E(yx)
.
B) xyE
.
C) Ey
.
D) yE
.
E) E2(xy)
.

To find the atomic mass of the metal \( M \) from its equivalent mass \( E \) and the molecular formula \( M_xO_y \), we will follow these steps:

1. **Understand Equivalent Mass:**
- The equivalent mass of a metal is defined as the mass of the metal that combines with 8 grams of oxygen.
- Equivalent mass, \( E \), is related to atomic mass, \( M_a \), by the number of electrons exchanged (n) in the redox reaction. \( E = \frac{M_a}{n} \).

2. **Oxide Formula Analysis:**
- The formula of the metal oxide is \( M_xO_y \).
- This means \( x \) atoms of the metal \( M \) combine with \( y \) atoms of oxygen \( O \).
- Each oxygen atom has a valency of 2, so the total positive charge contributed by \( x \) metal atoms must balance the total negative charge contributed by \( y \) oxygen atoms.
- The total negative charge by oxygen is \( 2y \).

3. **Calculating Equivalent Mass:**
- For \( x \) atoms of metal \( M \), the total valency (number of electrons transferred) is \( x \times \text{valency of } M = 2y \).
- So, valency of \( M = \frac{2y}{x} \).

4. **Relationship between Equivalent Mass and Atomic Mass:**
- Equivalent mass \( E \) is given by \( E = \frac{M_a}{\text{valency}} \).
- Hence, \( E = \frac{M_a}{\frac{2y}{x}} \).
- Rearrange to find the atomic mass \( M_a \):
\[
M_a = E \times \frac{2y}{x} = 2E \times \frac{y}{x}
\]

5. **Conclusion:**
- The atomic mass of the metal \( M \) is given by \( 2E \times \frac{y}{x} \).

So, the correct option is:
**(A) \( 2E \left(\frac{y}{x}\right) \)**.