Question

which metal is not affected by water? a)calcium b)sodium c) potassium d) Boron.

Answer 1

(a) $Ca+H_{2}O$ ⇒ $Ca(OH)_{2}+ H_{2}$

(b) $Na+H_{2}O$ ⇒ $NaOH+H_{2}$

(c) $K+H_{2}O$ ⇒ $KOH+H_{2}$

(d) $B+H_{2}O$ ⇒ No reaction under normal conditions

Also, Calcium, Sodium and Potassium are metals which are highly reactive with water

Answer 2

Answer:

When a metal and water react, hydrogen gas and metal hydroxide are produced. Some metals respond violently even when exposed to cold water, whereas others react only when exposed to hot water. Some metals also react when exposed to steam, while others do not.

Explanation:

Calcium metal interacts with water, less violently than other metals. The hydrogen gas bubbles produced by this process bind to the surface of calcium to form calcium hydroxide, a cloudy, white precipitate.

              Ca (s) + 2H₂O (l) → Ca(OH)₂ (aq) + H₂↑

Water and sodium metal react quickly to produce colorless sodium hydroxide (NaOH) solution and hydrogen gas (H2). Exothermic is the reaction. The sodium metal may get so heated during the reaction that it ignites and burns with a distinctive orange color.

                Na (s) + H₂O (l) → NaOH (l) + H₂ (g) ↑

When potassium metal and water interact, potassium hydroxide and hydrogen gas are produced.

                          2K + H₂O → 2KOH  + H₂ (g) ↑

Boron does not react with water as it has low reactivity than water.

Hence, the correct option is (d) Boron.

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