Question

An element is soft and can be cut easily with a knife. It is very reactive and cannot be kept open in the air. It reacts vigorously with water. This element is most likely to be:
A. magnesium
B. potassium
C. phosphorous
D. aluminium

Answer 1

Answer:

potassium is so.

Explanation:

hope u got ur answer

Answer 2

B. Potassium

Explanation:

Potassium (K) is an alkali metal. It is so soft that it can be cut with a knife. Potassium tarnishes quickly in air due to a reaction of oxygen and moisture. So it cannot be kept in open air. Potassium reacts very rapidly with water to form a colourless solution of potassium hydroxide (KOH) and hydrogen gas (H2).

Option B is the answer.