Question

19. How metal reacts with
a. oxygen
b. water
c. Acids​

Answer 1

Answer:

✯How metal reacts with oxygen

☆Answer:

Reactions of metals with oxygen in air

Many metals react with oxygen to form metal oxides. Potassium and sodium are soft metal which are easily cut exposing a shiny surface which changes to dull rapidly. The change from shiny to dull is called tarnishing.

✧For example:

Potassium burns with a lilac flame when heated in air.

potassium + oxygen ➞ potassium oxide

4K(s) + O2(g) ➞ 2K2O(s)

Magnesium reacts readily in air burning with a white light.

magnesium + oxygen ➞ magnesium oxide

2Mg(s) + O2(g) → 2MgO(s)

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✯How metal reacts with water

☆Answer:

Some metals react with water to form metal hydroxide and hydrogen gas.

$</p><p>2Na(sodium)+2H_{2}O⟶2NaOH+H {2} (hydrogen gas liberated)↑$

Less active metals react with boiling water. Generally non-metals do not react with water.

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✯How Does Metal React With Acid?

☆Answer:

Acids react with most metals to form hydrogen gas and a salt. Nevertheless, not all metals react in the same way to acids, and some metals are more resistant than others to corrosion. When an acid reacts with metal salt and hydrogen gas are produced. Metals which are more active than acids may experience a single displacement reaction.

✧For Example:

Zinc powder reacts with hydrochloric acid that releasesH2 gas and zinc chloride.

$</p><p></p><p>Zn(s)+2HCl(aq)→ZnCl {2} (aq)+H {2} (g)</p><p></p><p> </p><p></p><p>$

The salt that is produced depends upon acid and metal reacting.

Metals react with dilute hydrochloric acid to form the corresponding chloride salt and hydrogen which is evolved as bubbles. The rate of formation of bubbles was the fastest in case of magnesium.

The reaction was also the exothermic reaction and the reactivity decreases in the order

Mg > Al> Zn > Fe.

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