Which of the following metals is in liquid state at room temperature?

Correct option is B

Correct Answer: b. Mercury. Explanation: Mercury is a metal that is liquid at room temperature (around 20°C). In fact, mercury’s melting point is about –39°C, so it remains liquid at any typical ambient temperature. It is famously the only metal that is liquid at standard conditions​. This unique property is why mercury is also called “quicksilver.” Why other options are incorrect:
· Sodium: Sodium is a metal, but it is solid at room temperature. Sodium’s melting point is about 97.8°C, which means you would have to heat it to nearly 100°C for it to turn liquid. At normal room temperature, sodium stays in a solid metallic form (it’s a soft metal, but solid nonetheless).
· Coal: Coal is not a metal at all – it’s a form of carbon (usually a mixture of carbon and other elements) and is solid at room temperature. Since the question asks for a metal in liquid state, coal doesn’t qualify on two counts (not a metal, and it’s solid).
· Sulphur: Sulphur (sulfur) is a non-metal element that is solid at room temperature. Its melting point is about 115°C, so at room temperature sulfur remains a solid crystal. It is not a metal and does not become liquid until heated well above room temperature. Thus, neither coal nor sulfur are liquid metals at room temp – only mercury fits the description.