Question

Most reactive element among the following is:

• A. Hydrogen
• B. Calcium
• C. Sodium
• D. Copper

Answer 1

The correct option is C

Sodium

Electrochemical series:

1. It is a series of elements or molecules arranged according to their tendency to gain or lose electrons to form ions.
2. Most reactive element is placed at top while less reactive is placed below.

Explanation for the correct answer:

Option C: Sodium$\left(\mathrm{Na}\right)$

1. Among the given options Sodium$\left(\mathrm{Na}\right)$ lies at the top of the electrochemical series as shown above.
2. So Sodium is the most reactive element.

Explanation for the incorrect answer:

Option A: Hydrogen$\left(\mathrm{H}\right)$

Hydrogen $\left(\mathrm{H}\right)$ placed much below in the series is less reactive, only more reactive than opper$\left(\mathrm{Cu}\right)$

Option B: Calcium$\left(\mathrm{Ca}\right)$

Placed at $3^{\mathrm{rd}}$ position in the series, only more reactive metals are $\mathrm{K}\mathrm{and}\mathrm{Na}$

Option D: Copper$\left(\mathrm{Cu}\right)$

Placed below Hydrogen$\left(\mathrm{H}\right)$, it is the least reactive element among the given options.

So, Option C is correct. Sodium$\left(\mathrm{Na}\right)$ is the most reactive element among the given options.