Question

The lightest liquid metal is

• A. $\mathrm{Hg}$
• B. $\mathrm{Na}$
• C. $\mathrm{Cs}$
• D. $\mathrm{Fr}$

Answer 1

The correct option is C

$\mathrm{Cs}$

Explanation for correct option

(c ) $\mathrm{Cs}$

• At ambient temperatures, it is liquid.
• It is less heavy than $\mathrm{Hg}$ (also a liquid metal).
• The density of $\mathrm{Cs}$is $1.83{\text{g cc}}^{-1}$.
• Hence this is the correct option.

Explanation for incorrect options

(a) $\mathrm{Hg}$

• Even though mercury is liquid at room temperature but it is heavier than $\mathrm{Cs}$.
• The density of $\mathrm{Hg}$is $13.59{\text{g cc}}^{-1}$.
• Hence this is the incorrect option.

(b) $\mathrm{Na}$

• $\mathrm{Na}$ is solid at room temperature .
• The density of $\mathrm{Na}$is $0.971{\text{g cc}}^{-1}$
• Hence this is the incorrect option.

(d) $\mathrm{Fr}$

• $\mathrm{Fr}$ is solid at room temperature .
• The density of $\mathrm{Fr}$ is $2.48{\text{g cc}}^{-1}$
• Hence this is the incorrect option.

So, option (C )is the correct answer. The lightest liquid metal is $\mathrm{Cs}$.density of cesium