Precipitation reaction is a chemical reaction used to separate the insoluble solid to the aqueous solution. This is a technique that is usually used to separate the impurities. By knowing the right chemical to react with, only the pure acid will react and dissolve with ether. The impurity will be precipitated and will settle to the bottom.
Answer:
(D) (CH3CH2)2NH
Explanation:
In order to decide which base is strongest we need to calculate its PKb
PKb = -log [Kb]
A large Kb value and small PKb value gives the strongest base
Compound Kb PKb
(A) C6H5NH2 - 4 x 10^-10 9.349
(B) NH3 1.76x 10^-5 4.754
(C) CH3NH2 4.4x 10^-4 3.357
(D) (CH3CH2)2NH 8.6x 10^-4 3.066
(E) C5H5N 1.7x10^-9 8.77
Clearly (CH3CH2)2NH is the strongest base.
Second one i think.......
Question 4: C
question 5: D
