Question

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

(a) Mg

(b) Na

(c) P

(d) Ca
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Answer 1

Answer: (b) Na

Explanation: Na is a metal which is soft enough to be cut with a knife. It is so reactive that it reacts vigorously with air or moisture and catches fire when kept in open. So to prevent it from coming in contact with oxygen and moisture, it is kept in kerosene.

hope it's helps you ❤️

Answer 2

Answer:

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

(a) Mg

(b) Na✔✔

(c) P

(d) Ca