Question

7. What happens when :
(i) calcium reacts with water?
(ii) magnesium reacts with hot water?
(iii) sodium reacts with water?
(iv) iron reacts with steam?​

Answer 1

Answer:

Explanation:

(i) Calcium reacts with water?

Answer : Calcium reacts slowly with water. ... The reaction forms calcium hydroxide, Ca(OH)2 and hydrogen gas (H2). The calcium metal sinks in water and after an hour or so bubbles of hydrogen are evident, stuck to the surface of the metal.

(ii) Magnesium reacts with hot water?

Answer : Magnesium reacts with hot water much faster to produce magnesium hydroxide and hydrogen gas. Magnesium hydroxide is insoluble in water and is slightly basic, which reacts with the universal indicator, turning the solution blue/green or with phenolphthalein to turn the solution pink.

(iii) Sodium reacts with water?

Answer : Sodium metal reacts rapidly with water to form a colourless solution of sodium hydroxide (NaOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. ... During the reaction, the sodium metal may well become so hot that it catches fire and burns with a characteristic orange colour.

(iv) Iron reacts with steam?

Answer : When a metal reacts with steam then the products formed are metal oxide and hydrogen gas. When red hot iron reacts with steam to form iron(II,III) oxide and hydrogen. Properties: ... Fe is turned into ferrous oxide FeO, ferric Oxide (haematite) Fe2O3 F e 2 O 3 or magnetite Fe3O4 F e 3 O 4 .

Hope it helps.

Answer 2

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Answers:

(i) Calcium reacts with water slowly. The reaction of calcium with water forms Calcium hydroxide.

Ca(OH)2 and hydrogen gas (H2).

(ii) Magnesium reacts with hot water much faster to produce magnesium hydroxide and hydrogen gas. Magnesium hydroxide is insoluble in water Mg(OH2)

(iii) Sodium metal reacts rapidly with water to form a colourless basic solution of sodium hydroxide (NaOH) and hydrogen gas (H2).

(iv) iron reacts with steam then it formed iron oxide.

Reaction: 3Fe + 4H2O⟶ Fe3O4 + 4H2