A student performed the first set of
experiments with four test tubes containing
solutions and metal pieces as indicated in
the figure. In the second set of experiments,
the metal pieces are interchanged between
test tubes P and Q and also between test
tubes R and S.
In which test tube(s), no reaction will occur in both sets of experiments?
A P and Q
B R
C S
D R and S.
answer is R
Ans 4:
Class : Class 8
The answer stated is wrong (which is stated as D) and the solution given favours answer B!
Ans 5:
Class : Class 8
But in the second set of experiments, a reaction will occur, since the iron will be replaced by zinc and zinc is more reactive than copper and iron. Hence, the answer should be R.