Given below are reactions involving metals P, Q, R and S and their salt solutions in water.
Metal P salt solution `+ Q to` Metal Q salt solution + P
Metal Q salt solution `+ R to` Metal R salt solution + Q
Metal S salt solution `+ Q to` Metal Q salt solution + S
Metal P salt solution + S `to` No reaction
Which metal is the MOST reactive?

Options

A. P
B. Q
C. R
D. S

Answer

To determine which metal is the most reactive among P, Q, R, and S based on the given reactions, we can analyze each reaction step by step.

### Step 1: Analyze the first reaction
**Reaction:** Metal P salt solution + Q → Metal Q salt solution + P

In this reaction, metal Q displaces metal P from its salt solution. This indicates that metal Q is more reactive than metal P.

### Step 2: Analyze the second reaction
**Reaction:** Metal Q salt solution + R → Metal R salt solution + Q

Here, metal R displaces metal Q from its salt solution. This means that metal R is more reactive than metal Q.

### Step 3: Analyze the third reaction
**Reaction:** Metal S salt solution + Q → Metal Q salt solution + S

In this case, metal Q displaces metal S from its salt solution. This indicates that metal Q is more reactive than metal S.

### Step 4: Analyze the fourth reaction
**Reaction:** Metal P salt solution + S → No reaction

Since there is no reaction between metal P and metal S, it indicates that metal P is more reactive than metal S.

### Summary of Reactivity
From the analysis, we can summarize the reactivity of the metals as follows:
1. R is more reactive than Q (from Step 2).
2. Q is more reactive than P (from Step 1).
3. Q is more reactive than S (from Step 3).
4. P is more reactive than S (from Step 4).

### Final Order of Reactivity
Based on the above deductions, we can establish the order of reactivity:
- R > Q > P > S

Thus, the most reactive metal among P, Q, R, and S is **R**.