Question

An element A is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in air. It reacts vigorously with water. Identify the element from the following

Options

• Mg

• Na

• P

• Ca

Answer 1

Na

Explanation - 

Sodium is a third-period alkali metal which is a soft metal and highly reactive. sodium is stored under kerosene and whenever it comes in contact with air or water it reacts vigorously.