For and elementary reaction
`2A underset(k_(2))overset(k_(1))hArr B`, the rate of disappearance of `A` iss equal to
(a) `(2k_(1))/(k_(2))[A]^(2)`
(b) `-2k_(1)[A]^(2) + 2k_(2)[B]`
( c) `2k_(1)[A]^(2) - 2k_(2)[B]`
(d) `(2k_(1) - k_(2))[A]`

Explanation

To solve the problem regarding the rate of disappearance of A in the reaction `2A ⇌ B`, we will follow these steps:

### Step 1: Write the Rate Expressions
For the forward reaction `2A → B`, the rate can be expressed as:
\[ R_f = k_1 [A]^2 \]
where \( k_1 \) is the rate constant for the forward reaction.

For the reverse reaction `B → 2A`, the rate can be expressed as:
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