For a given reaction, 
Cu(s) + 2Ag⁺ (aq) → Cu²⁺(aq)+2Ag(s); 
E⁰=0.46 V at 298 K . The equilibrium constant will be :

1. $2.4\times {10}^{10}$

2. $2.0\times {10}^{10}$

3. $4.0\times {10}^{10}$

4. $4.0\times {10}^{15}$

A hypothetical electrochemical cell is shown below.
A|A⁺(x M) || B⁺(y M)|B
The Emf measured is +0.20 V. The cell reaction is:

1. A⁺ + B → A + B⁺

2.  A⁺ + e^- → A ; B⁺ + e^- → B

3. The cell reaction cannot be predicted.

4. A + B⁺ → A⁺ + B