Question

a reaction A(g)⇌B(g)has an equilibrium constant of 1.0×10−4 For which of the initial reaction mixtures is the small approximation most likely to apply? Explain why.

Answer 1

Answer:

4. [A] = 0.10M; [B] = 0.00M

Explanation:

Hello,

In this case, the following options are missing:

1. [A] = 0.00M; [B] = 0.10M

2. [A] = 0.0010M; [B] = 0.00010M

3. [A] = 0.10M; [B] = 0.10M

4. [A] = 0.10M; [B] = 0.00M

Therefore, since the equilibrium constant is small, one could make up that at the beginning there is no B since not too much A is consumed during the reaction, consequently, the answer is:

4. [A] = 0.10M; [B] = 0.00M

In fact, $x$ in this case would be 0.00001M which is the smallest one from the given options, considering:

$1x10^{-4}=\frac{x}{0.1-x}$

Best regards.