Question

Which of the given metals exhibits both reactions (a) as well as (b)?

(a) Metal + Oxygen $\to$ Metal oxide

(b) Metal + Cold water or hot water or steam $\to$ Metal hydroxide + Hydrogen

• A. Magnesium (Mg), iron (Fe), sodium (Na), and copper (Cu)
• B. Magnesium (Mg), zinc (Zn), platinum (Pt), and gold (Au)
• C. Sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca)
• D. Copper (Cu), magnesium (Mg), gold (Au), and sodium (Na)

Answer 1

The correct option is C Sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca)

Sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) react with oxygen to form their respective metal oxides. Sodium, potassium and calcium being very reactive, react with cold water, hot water and steam. However, magnesium is less reactive than these three and reacts with only hot water and steam.

Iron (Fe) reacts with both oxygen and steam. Copper (Cu) reacts with oxygen but is unreactive with any form of water.

Platinum (Pt) and gold (Au) are unreactive towards both water and oxygen.

Hence, the elements showing both reactions are sodium (Na), potassium (K), magnesium (Mg) and calcium (Ca).