question_answer

A student took four test tubes P, Q, R and S and filled about 8 ml. of distilled water in each after that he dissolved an equal amount of  \[\mathbf{N}{{\mathbf{a}}_{\mathbf{2}}}\mathbf{S}{{\mathbf{O}}_{\mathbf{4}}}\] in P, \[{{\mathbf{K}}_{\mathbf{2}}}\mathbf{S}{{\mathbf{O}}_{\mathbf{4}}}\] in Q, \[\mathbf{CaS}{{\mathbf{O}}_{\mathbf{4}}}\] in R and \[\mathbf{MgS}{{\mathbf{O}}_{\mathbf{4}}}\]in. On adding an equal amount of soap solution and        shaking each test tube well, a good amount of lather will be obtained in the test tubes:

(a) P and Q

(b) P and R

(c) P, Q and S

(d) Q, R and S

 

Answer:

(a) P and Q