Chemical Reactions of Acids
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Acid reacting with Metals
Acid reacts with Metals to form Salt and Hydogen gas is also released.
Acid + Metals → Salt + Hydrogen Gas
When Zinc (Zn) reacts with dilute Sulphuric Acid (H 2 SO 4 ) , it produces a salt called Zinc Sulphate (ZnSO 4 ) and Hydrogen Gas.
Zn(s) + H 2 SO 4 (aq) → ZnSO 4 (aq) + H 2 (g)
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Acid reacting with metal carbonates and metal hydrogen carbonates
Acid Reacts with Metal Carbonates to form Salt, water and release Carbon DioxideAcid + Metal Carbonate → Salt + Carbon Dioxide + Water
Note : The carbon dioxide released is in the form of brisk effervescence (subtle white smoke).
For example
i.) When dilute Hydrochloric Acid reacts with Sodium Carbonate , it produces a salt called Sodium Chloride, Water and Carbon Dioxide is released.
2HCl(aq) + Na 2 CO 3 (s) → 2NaCl(aq)+ H 2 O(l) + CO 2 (g)
ii.) When Hydrochloric Acid reacts with Sodium Hydrogen Carbonate, it produces a salt called Sodium Chloride, water and Carbon Dioxide.
Acid + Metal Hydrogen Carbonate → Salt + Carbon Dioxide + Water
HCl(aq) + NaHCO 3 (s) → NaCl(aq)+ H 2 O(l) + CO 2 (g)
Note : The carbon dioxide released is in the form of brisk effervescence (subtle white smoke).
- The CO 2 evolved in the above reactions when passed through lime water ( Ca(OH) 2 Solution) turns the lime water milky due to the formation of white coloured precipitate of Calcium Carbonate (CaCO 3 ).
Ca(OH) 2 (aq) + CO 2 (g) → CaCO 3 (s) + H 2 O(l)
- If excess Carbon Dioxide (CO 2 ) is passed through lime water over a prolonged period of time , the lime water again returns to a colourless liquid as the milkiness disappears due to the formation of a soluble salt called Calcium Hydrogencarbonate (Ca(HCO 3 ) 2 ) .
CaCO 3 (s) + CO 2 (g) + H 2 0 (l) → Ca(HCO 3 ) 2 (s)
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Acid reacting with Metallic Oxides and Metal Hydroxide
Acids react with Metal Oxides to form Salt and Water
Acid + Metal Oxide/Metal Hydroxide → Salt + Water
When Dilute Hydrochloric acid reacts with Copper (II) Oxide (CuO) , it forms a salt called Copper (II) Chloride (CuCl 2 ) and Water(H 2 0).
CuO (s) + HCl (aq) → CuCl 2 (s) + H 2 O (l)
NCERT Question - Q3, Q4, Q14
Intext Question - Page 22 Q1, Q2, Q3
NCERT Question - Q3, Q5
Intext Question - Page 25 Q1, Q2, Q3
NCERT Question - Q6, Q8
Chemical Reactions of Bases
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Reaction of Base with Metals
This reaction leads to the formation of a salt and hydrogen gas is also released.
Base + Metal → Salt + Hydrogen Gas
When Sodium hydroxide (NaOH, a base) is heated with Zinc (Zn, a metal),it forms Sodium Zincate (Na2ZnO2, a salt) and Hydrogen Gas (H2). This hydrogen gas produces a pop sound
2NaOH (aq) +Zn (s) →Na 2 ZnO 2 (aq) + H 2 (g)
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Reaction of Base with Non-Metal Oxides:
Base reacts with Non-metal Oxides to form Salt and water
Non-Metal Oxide + Base → Salt + Water
When Calcium Hydroxide ( Ca(OH) 2 , a base) reacts with Carbon Dioxide (CO 2 , a Non-metal Oxide) , it results in the formation of the salt Calcium Carbonate ( CaCO 3 ) and Water ( H 2 O).
Ca(OH) 2 (aq) + CO 2 (g) → CaCO 3 (s) + H 2 O (l)
Note : Since this is a form of a neutralisation reaction which yields salt and water , we can conclude that CO 2 is and Acid since it neutralises Ca(OH) 2