Q. A student takes about 4 ml of distilled water in four test tubes marked
P, Q, R and
S. He then dissolves in each test tube, an equal amount of various salts, viz. sodium sulphate in
P, potassium sulphate in
Q, calcium sulphate in
R and magnesium sulphate in
S. After that, he adds an equal amount of soap solution in each test tube. On shaking each of these test tubes well, he observes a good amount of lather (foam) in the test tube marked:
- Q and R
- P, Q and S
- P and Q
- P, R and S