Question

give balance eq: nh4oh solution is added to zn(no3)2 solution till in excess​

Answer 1

Answer:

Explanation:

I assume NH3 here refers to its aqueous solution. That is a typical alkali reaction in which the alkali reacts with a metal salt to give a metal hydroxide. Note that the final products depend on whether ammonia is in excess. If it is, a further reaction takes place.

For simplicity, I’ll show the ionic equations instead of complete chemical equations.

(First) reaction:

Zn2

+(aq)+2OH−(aq) -> Zn(OH)2(s)

A white gelatinous precipitate is formed.

If you continue to add ammonia solution until it is in excess, the following reaction occurs to have the precipitate redissolve to leave a colourless solution, for the insoluble zinc hydroxide is converted to soluble tetraamminezinc (II) ion (yes, it has 2 ms due to historical reasons).

Zn(OH)2(s)+4NH3(aq)

->[Zn(NH3)4]2+(aq)+OH−(aq)