Metals which are high above in the activity series react with normal water to replace H2, whereas those below it displaces H2 from hot water/Steam. Metals below them can replace H2 from acids. But the Metals very below H2 in the series cannot displace H2 on reaction with any of these three. Thus, from the given metals, S is least reactive as it did not react with water at all, R is most reactive as it reacted violently with cold water, Q is second most reactive metal as it reacted with hot water to displace H2 and P is third most reactive metal as it did not reacted with hot or cold water but reacted with steam. Hence the correct order of reactivity is :
S<P<Q<R
Case-II:
The figure shown below represents a common type of dialysis called as Hemodialysis. It removes waste products from the blood. Such as excess salts, and urea which are insufficiently removed by the kidney in patients with kidney failure. During the procedure, the patient's blood is cleaned by filtration through a series of semi-permeable membranes before being returned to the blood of the patient. On the basis of this, answer the following questions: