Answer:
A. When two aqueous solutions are mixed, a precipitate is formed.
Explanation:
The precipitate (a solid substance that falls from the liquid) is the result of a chemical reaction taking place between the liquids.
The other three answer choices are indicative of physical changes (temperature change, phase change, color change).
Answer: -
When bismuth-212 undergoes alpha decay, it becomes ²⁰⁸Tl
Explanation: -
Mass number of ²¹²Bi = 212
Atomic number of ²¹²Bi = 83
When alpha decay occurs the mass number decreases by 4 and the atomic number decreases by 2.
Mass number of daughter = 212 - 4 = 208
Atomic number of daughter = 83 - 2 = 81
It is the atomic number of Thallium Tl.
Thus the daughter nucleide is ²⁰⁸Tl.
