Question

Which of the following metals is brittle and crumbles into powder?

• A. Mercury
• B. Zinc
• C. Potassium
• D. Calcium

Answer 1

The correct option is B

Zinc

The explanation for the correct option:
(B) Zinc

• Metals possess metallic luster, i.e., they have a shining surface.
• Metals are ductile (can be drawn into wires) and malleable (can be beaten into sheets).
• Exception: Zinc is brittle and crumbles into powder.

The explanation for incorrect options:
(A) Mercury

• Metals are hard solids, i.e., they possess high tensile strength (cannot be broken easily).
• Exception: Mercury and gallium are found in a liquid state.

(C) Potassium

• Sodium and potassium are soft metals.
• It can be cut with a knife

(D) Calcium

• Metals have high melting and boiling points.
• Exception: Metals like potassium, calcium, and sodium have low melting and boiling points.
  
• Hence option B is correct.