Question

A metal which reacts with cold water vigorously producing hydrogen is

• A. Gold
• B. Tin
• C. Sodium
• D. Tungsten

Answer 1

The correct option is C

Sodium

Explanation for correct option:

(C) Sodium

Reaction of metal with cold water:

• Alkali metals usually have higher reactivity than other metals.
• Thus an alkali metal can react vigorously with cold water producing Hydrogen gas.
• This reaction is highly exothermic in nature.
• The metals such as Sodium, Lithium, and Potassium.
• The reaction of an alkali metal with cold water produces metal hydroxide. The chemical reaction can be depicted as:

$\mathrm{Alkali}\mathrm{metal}+\mathrm{water}\to \mathrm{Metal}\mathrm{Hydroxide}+\mathrm{Hydrogen}$

Reaction of Sodium with cold water:

• When Sodium$\left(\mathrm{Na}\right)$ metal reacts with cold water, it produces sodium hydroxide$\left(\mathrm{NaOH}\right)$ and hydrogen gas$\left({\mathrm{H}}_2\right)$ is released.
• The chemical reaction is depicted below:

$$\begin{gathered} 2\mathrm{Na}\left(\mathrm{s}\right)+2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\mathrm{NaOH}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right) \\ \left(\mathrm{Sodium}\right)\left(\mathrm{Water}\right)(\mathrm{Sodium}\mathrm{hydroxide})\left(\mathrm{Hydrogen}\right) \end{gathered}$$

Explanation for incorrect options:

A. Gold is a transition metal and it will not react with cold water.

B. Tin is a non-metal and it will not react with cold water.

D. Tungsten is a transition metal and it will not react with cold water.

Hence the correct option is C i.e. Sodium.