Question

Consider the following properties of an element:

(i) It is solid at room temperature.
(ii) It easily forms an oxide when exposed to air.
(iii) When it reacts with water, hydrogen gas evolves.
(iv) It must be stored submerged in oil.

Which element fits the above description the best?

a. Sodium
b. Copper
c. Mercury
d. Sulfur
e. Magnesium

Answer 1

Sodium is the element that matches the description of being a solid at room temperature, forming an oxide easily with air, reacting with water to release hydrogen, and needing to be stored in oil to prevent reactions.

Step-by-step explanation:

The element that best fits the description provided is sodium (Na). This element is a solid at room temperature and easily reacts with both oxygen and water. When exposed to air, sodium forms an oxide, and when it reacts with water, hydrogen gas is released, which can be observed as fizzing.

Furthermore, sodium is a highly reactive metal that must be stored in oil, such as mineral oil, to prevent it from reacting with air or water and to keep it from igniting spontaneously. These properties align with the clues given in the schoolwork question.