If the K_b values of ammonia, methylamine and ethylamine are x, y and z respectively, identify the correct relation between x, y and z from the following.

x > y > z

The correct answer is option 3. x > y > z.

The \( K_b \) (base dissociation constant) values of amines are related to their basicity. A higher \( K_b \) value indicates a stronger base and therefore higher basicity.

Given the options:

1. \( x > z \): This option suggests that the \( K_b \) value of ammonia is greater than that of ethylamine. This could be plausible because ammonia is more basic than ethylamine.

2. \( x > y \): This option suggests that the \( K_b \) value of ammonia is greater than that of methylamine. This is also plausible as ammonia is more basic than methylamine.

3. \( x > y > z \): This option suggests that the \( K_b \) value of ammonia is greater than that of methylamine, and the \( K_b \) value of methylamine is greater than that of ethylamine. This is plausible based on the typical trend in basicity: ammonia > methylamine > ethylamine.

4. \( y < z \): This option suggests that the \( K_b \) value of methylamine is less than that of ethylamine. This is unlikely because methylamine is generally more basic than ethylamine.

Therefore, the correct relation based on the options provided is Option 3: \( x > y > z \).