Answer : The balanced chemical equation in a basic solution are,
(A) 
(B) 
(C) ![4Zn+7OH^-+NO_3^-+6H_2O\rightarrow 4[Zn(OH)_4]^{2-}+NH_3](https://tex.z-dn.net/?f=4Zn%2B7OH%5E-%2BNO_3%5E-%2B6H_2O%5Crightarrow%204%5BZn%28OH%29_4%5D%5E%7B2-%7D%2BNH_3)
(D) 
Explanation :
<u>(A) The given chemical reaction is :</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
In order to balance the electrons, we multiply the oxidation reaction by 3 and reduction reaction by 2 then added both equation, we get the balanced redox reaction.
The balanced chemical equation in a basic solution will be,

or,

<u>(B) The given chemical reaction is :</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
The electrons in both the reactions are balanced. Now added both equation, we get the balanced redox reaction.
The balanced chemical equation in a basic solution will be,

<u>(C) The given chemical reaction is :</u>

The oxidation-reduction half reaction will be :
Oxidation : ![Zn+4OH^-\rightarrow [Zn(OH)_4]^{2-}+2e^-](https://tex.z-dn.net/?f=Zn%2B4OH%5E-%5Crightarrow%20%5BZn%28OH%29_4%5D%5E%7B2-%7D%2B2e%5E-)
Reduction : 
In order to balance the electrons, we multiply the oxidation reaction by 4 and then added both equation, we get the balanced redox reaction.
The balanced chemical equation in a basic solution will be,
![4Zn+7OH^-+NO_3^-+6H_2O\rightarrow 4[Zn(OH)_4]^{2-}+NH_3](https://tex.z-dn.net/?f=4Zn%2B7OH%5E-%2BNO_3%5E-%2B6H_2O%5Crightarrow%204%5BZn%28OH%29_4%5D%5E%7B2-%7D%2BNH_3)
<u>(D) The given chemical reaction is :</u>

The oxidation-reduction half reaction will be :
Oxidation : 
Reduction : 
In order to balance the electrons, we multiply the reduction reaction by 5 and then added both equation, we get the balanced redox reaction.
The balanced chemical equation in a basic solution will be,
