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Question : 4
Total: 6
A metal ' M
(a) Name the metal 'M
(b) Write formula of the compound formed when this metal is exposed to air.
(c) Why is metal 'M
(d) If oxide of this metal is treated with hydrochloric acid, what would be the products ?
(e) Write balanced equation for :
(i) Reaction of 'M
(ii) Reaction of 'M
(iii) Reaction of metal oxide with hydrochloric acid.
OR
(a) Write electron dot structures ofCa O
(b) Show the formation of calcium oxide by transfer of electrons.
(c) Name the ions present in this compound.
(d) List four important characteristics of this compound.
(a) Name the metal '
(b) Write formula of the compound formed when this metal is exposed to air.
(c) Why is metal '
(d) If oxide of this metal is treated with hydrochloric acid, what would be the products ?
(e) Write balanced equation for :
(i) Reaction of '
(ii) Reaction of '
(iii) Reaction of metal oxide with hydrochloric acid.
OR
(a) Write electron dot structures of
(b) Show the formation of calcium oxide by transfer of electrons.
(c) Name the ions present in this compound.
(d) List four important characteristics of this compound.
Solution:
(a) Metal M-Sodium
4 Na + O 2 → 2 Na 2 O
(b) Sodium oxide
(c) Metals such as potassium and sodium react so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil.
(d) As a strong base, sodium oxide reacts with acids. It would react with dilute hydrochloric acid to produce sodium chloride solution.
Na 2 O + 2 HCl → 2 NaCl + H 2 O
(e) (i) Reaction of Metal "M" (Sodium) with air : Sodium reacts with air to form the sodium oxide.
4 Na + O 2 → 2 Na 2 O
(ii) Reaction of Metal "M" (Sodium) with water: Sodium reacts with water to form sodium hydroxide along with the evolution of heat energy.
2 Na ( s ) + 2 H 2 O ( l ) → 2 NaOH ( aq ) + H 2 ( g )
Heat energy
(iii) Reaction of metal oxide with hydrochloric acid : Sodium oxide reacts with hydrochloric acid to form sodium chloride and water.
Na 2 O + 2 HCl → 2 NaCl + H 2 O
(a) Electron dot structure ofCa
¨ C a
Electron dot structure ofO
⋅ Ö:
(b) Calcium reacts with oxygen to form an ionic compound calcium oxide( CaO ) ( Ca 2 + ) ( O 2 − )
( Ca 2 + ) ( O 2 − )
(d) Important characteristic of calcium oxide are:
(i) Calcium oxide reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of heat.
(ii) Quick lime is an amorphous white solid with a high melting point of2600 ∘ C
(iii) It is a very stable compound and withstands high temperatures.
(iv) Calcium oxide is very useful in the production of building materials such as cement and concrete, similar to other calcium compounds such as calcium sulphate.
(v) They conduct electricity in molten state.
(b) Sodium oxide
(c) Metals such as potassium and sodium react so vigorously that they catch fire if kept in the open. Hence, to protect them and to prevent accidental fires, they are kept immersed in kerosene oil.
(d) As a strong base, sodium oxide reacts with acids. It would react with dilute hydrochloric acid to produce sodium chloride solution.
(e) (i) Reaction of Metal "M" (Sodium) with air : Sodium reacts with air to form the sodium oxide.
(ii) Reaction of Metal "M" (Sodium) with water: Sodium reacts with water to form sodium hydroxide along with the evolution of heat energy.
Heat energy
(iii) Reaction of metal oxide with hydrochloric acid : Sodium oxide reacts with hydrochloric acid to form sodium chloride and water.
(a) Electron dot structure of
Electron dot structure of
(b) Calcium reacts with oxygen to form an ionic compound calcium oxide
(c) Ions present in this compound are calcium ion
(d) Important characteristic of calcium oxide are:
(i) Calcium oxide reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of heat.
(ii) Quick lime is an amorphous white solid with a high melting point of
(iii) It is a very stable compound and withstands high temperatures.
(iv) Calcium oxide is very useful in the production of building materials such as cement and concrete, similar to other calcium compounds such as calcium sulphate.
(v) They conduct electricity in molten state.
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