Answer :
YES, The precipitation reaction will occur.
Explanation : When we mix the aqueous solutions of Lead chloride and Ammonium sulfide a reaction will occur which is stated below :
![PbCl_{2} +(NH_{4}) _{2} S ----\ \textgreater \ PbS + 2[ (NH_{4})Cl]](https://tex.z-dn.net/?f=PbCl_%7B2%7D%20%2B%28NH_%7B4%7D%29%20_%7B2%7D%20S%20----%5C%20%5Ctextgreater%20%5C%20%20PbS%20%2B%202%5B%20%28NH_%7B4%7D%29Cl%5D%20)
The major product that is formed is Lead sulfate which is black in colour.
Once the reaction is complete one can observe a black precipitate getting obtained.
The symbol used to indicate a substance is (aq).
I would say c-gas because they float around and spread
Answer:
The pair co,Ni is out of order in terms of atomic mass
Explanation:
For co,Ni
Atomic mass of Co = 58.9331 u
Atomic mass of Ni = 58.6934
For Li,be
Atomic mass of Li = 6.941 u
Atomic mass of be = 9.012182 u
For I,xe
Atomic mass of I = 126.90447 u
Atomic mass of Xe = 131.293 u
Hence, the pair co,Ni is out of order in terms of atomic mass