How many moles of `NH_(3)` must be added to 1 litre of `0.1 ` M `AgNO_(3)` solution to reduce `Ag^(+)` concentration to `2xx10^(-7) " M "K_(d) [Ag (NH_(3))_(2)^(+)] = 6.8 xx10^(-8)` .

Explanation

To solve the problem of how many moles of `NH3` must be added to 1 litre of `0.1 M AgNO3` solution to reduce the `Ag^+` concentration to `2 x 10^(-7) M`, we will follow these steps:

### Step 1: Understand the Reaction and Given Data
We are given the dissociation constant \( K_d \) for the complex \( [Ag(NH_3)_2]^+ \) as \( 6.8 \times 10^{-8} \). The initial concentration of \( Ag^+ \) is \( 0.1 M \) and we want to reduce it to \( 2 \times 10^{-7} M \).

### Step 2: Write the Expression for the Dissociation Constant
The equilibrium expression for the formation of the complex ion \( [Ag(NH_3)_2]^+ \) can be written as:
\[
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