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Acids, Bases & Salts (B)
Q.1. From the list of the substances given below, choose the pair required to prepare the salts (i)
to (iii) in the laboratory and write down the relevant equations.
The substances are :
Iron, Chlorine, Lead Nitrate solution, Sodium Nitrate solution, Iron (III) Carbonate, Lead Carbonate,
Iron (III) Hydroxide, Sodium Hydroxide and dilute Hydrochloric acid.
(i) Sodium Chloride (ii) Lead Chloride (iii) Anhydrous Iron (III) Chloride.
Ans.: - (i) NaOH + HCl (dil) → NaCl + H2O
(ii) Pb(NO3)2+ 2HCl (dil) → PbCl2 + 2HNO3
(iii) 2Fe (heated) + 3Cl2 (dry) → 2FeCl3.
Q.2. All Ammonium salts are decomposed on heating. What other property do Ammonium salts
have in common?
Ans.: - All Ammonium salts are soluble in water.
Q.3. Answer the following questions, relating your answers only to salts in the list given below :
Anhydrous Calcium Chloride, Copper Sulphate-5-water, Sodium Carbonate-10 – water.
(a) Which compound is efflorescent?
(b) Which compound is blue in colour?
(c) Which compound is deliquescent?
(d) What would be seen on mixing a solution of Calcium chloride with a solution of Sodium
carbonate?
(e) Write the balanced equation for occurring when a solution of Calcium chloride is mixed with a
solution of Sodium carbonate.
Ans : - (a) SodiumCarbonate – 10 – water.
(b) Copper sulphate – 5 – water.
(c) Anhydrous Calcium chloride.
(d) A white precipitate of Calcium carbonate is formed.
(e) CaCl2 + Na2CO3 → CaCO3 ↓ + 2NaCl
Q.4. In this question, you are required to supply the word (or words) that will make the following
sentence into correct statement which is to be written down in full.
Calcium nitrate reacts with Sodium sulphate to form Calcium sulphate.
Ans.: - Calcium nitrate solution reacts with Sodium sulphate solution to form Calcium sulphate.
Q.5. Describe in each case, one chemical test that would enable you to distinguish between the
following pairs of chemicals. Describe what happens with each chemical or state “no visible
reason”.
(a) Sodium chloride solution and sodium nitrate.
(b) Sodium sulphate solution and Sodium chloride solution.
Ans : - (a)
Sodium chloride solution
Sodium nitrate solution
When sodium chloride
When sodium nitrate solution
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solution is treated with Silver
nitrate solution, a white
precipitate is formed which is
soluble in excess of
Ammonium hydroxide.
is treated with Silver nitrate
solution, no visible reaction is
observed.
b)
Sodium sulphate solution
Sodium chloride solution
When Sodium sulphate
solution is treated with Barium
chloride solution, a white
precipitate is formed which is
insoluble in all the mineral
acids.
When Sodium chloride
solution is treated with Barium
chloride solution, no visible
reaction is observed.
Q.6. Write balanced equations for each of the following reactions :
(a) Action of heat on Copper nitrate. (b) Zinc and dilute Sulphuric acid.
Ans.: - (a) 2Cu(NO3)2 + Δ → 2CuO + 4NO2 + O2.
(b) Zn + H2SO4 → ZnSO4 + H2.
Q.7. (a) Choose the correct word or phrase from the brackets to complete the following sentences
:
(i) Ammonium chloride is a soluble salt prepared by (precipitation, neutralization).
(ii) When Ammonium chloride is heated, it undergoes (thermal decomposition, thermal
dissociation).
(b) Write correctly the balanced equations for each of the reactions mentioned in the above
statements.
Ans.: - (a)(i) Neutralization. (ii) Thermal dissociation.
(b) NH4OH + HCl → NH4Cl + H2O
Δ
NH4Cl ↔ NH3 + HCl
cool
Q.8. Define the following terms :
(i) pH-scale (ii) Neutralization.
Ans.: - (i) pH-scale – It is a scale to tell whether a given solution is acidic, alkaline or neutral in nature.
(ii) Neutralization – It is a process when Hydrogen ions, derived from an acid, combine with Hydroxyl ions,
derived from base, forming unionized water molecule.
Q.9. (i) Outline the steps that would be necessary to convert insoluble Lead (II) oxide into
insoluble Lead chloride.
(ii) Write the balanced equations for the reaction required to convert insoluble Lead (II) oxide into
insoluble Lead chloride.
(iii) If iron reacts with dilute sulphuric acid, what will be the products of sulphuric acid?
(iv) A solution of Iron (III) chloride has a pH less than 7.Is the solution acidic or alkaline?
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Ans.: - (i) Lead oxide is treated with dilute nitric acid to get soluble Lead nitrate. This Lead nitrate is
treated with soluble Metallic chloride or dilute hydrochloric
acid to get insoluble Lead chloride.
(ii) PbO + 2HNO3 (dil) → Pb(NO3)2 + H2O
Pb(NO3)2 + 2NaCl → PbCl2 + 2NaNO3.
(iii) The product will be Ferrous sulphate / Iron (II) Sulphate.
Fe + H2SO4 (dil) → FeSO4 + H2.
(iv) Acidic.
Q.10. From the following list of substances, choose the one substance in each case which
matches the description (a) to (f) given below :
(Write down the names exactly as they are given in the list. Do not write formulae.)
Ammonium nitrate, Calcium Hydrogen carbonate, Copper Carbonate, Lead carbonate, Lead
nitrate, Potassium nitrate, Sodium carbonate, Sodium Hydrogen carbonate, Zinc carbonate.
(a) A Hydrogen carbonate which exists in the solid state.
(b) A carbonate not decomposed by heat.
(c) A green coloured Carbonate which turns black on heating.
(d) a nitrate which gives off only Oxygen when heated.
(e) A nitrate which on heating decomposes into Dinitrogen oxide (Nitrous oxide) and steam.
(f) A nitrate which gives off Oxygen and Nitrogen dioxide when heated.
Ans.: - (a) Sodium hydrogen carbonate (b) Sodium carbonate (c) Copper carbonate (d) Potassium nitrate
(e) Ammonium nitrate (f) Lead nitrate.
Q.11. Some methods used for the laboratory preparation of salt are
A – Metal + acid
B – Carbonate + acid
C – Precipitation
D – Direct combination
E – Titration
Copy and complete the following table :
Salt
Method of
Preparation
mmonium
sulphate
Titration
Calcium
carbonate
Iron (III) chloride
Lead nitrate
Zinc sulphate
Ans.: Salt
Method of Preparation
Ammonium
sulphate
Titration
Calcium carbonate
Precipitation
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Iron (III) chloride
Direct combination
Lead nitrate
Carbonate + acid / Metal +
acid
Zinc sulphate
Metal + acid
Q.12. What do you see when concentrated Sulphuric acid is added to Copper sulphate-5-water.
Ans.: - When concentrated Sulphuric acid is added to blue coloured crystalline Copper sulphate-5-water,
it crumbles down to a white amorphous powder by loosing water of crystallization.
Q.13. Name (formula not acceptable) the gas produced in the following reaction:
Warming Ammonium sulphate solution with Sodium Hydroxide solution.
Ans.: - Ammonia.
Q.14. State what do you observe when :
(a) Neutral litmus solution is added to an alkaline solution.
(b) Lead nitrate solution and Sodium chloride solution are mixed.
Ans.: - (a) The colour of litmus changes to blue.
(b) A white precipitate soluble in hot water and insoluble in cold water is formed.
Q.15. Copy and complete the table. The table summarizes the observations following the addition
of Barium chloride solution and Lead nitrate solution to solution of Zinc salt. If nothing happens
write no reaction as shown or write white precipitate.
Barium chloride
solution
Lead nitrate
solution
Zinc
chloride
solution
Zinc
nitrate
solution
No reaction
Zinc
sulphate
solution
Ans.: Barium
chloride
solution
Lead
nitrate
solution
Zinc chloride solution
No
reaction
White
precipitate
Zinc nitrate solution
No
No
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reaction
Zinc sulphate solution
reaction
White
White
precipitate precipitate
Q.16. Write the balanced equations for the following reactions:
(a) Dilute hydrochloric and Sodium sulphite.
(b) An acid and an alkali. (Yoy must first write : “The acid is ______ and the alkali is _______. “
then write the equation)
Ans.: - (a) Na2SO3 + 2HCl → 2NaCl + H2O + SO2
(b) The acid is – Sulphuric acid or Nitric acid or Hydrochloric acid. The alkali is – Sodium hydroxide or
potassium hydroxide.
H2SO4 (dil) + 2KOH → K2SO4 + 2H2O
HNO3 (dil) + KOH → KNO3 + H22O
HCl (dil) + NaOH → NaCl + H2O
Q.17. Write the terms defined by the following sentences :
(a) A soluble base.
(b) The insoluble solid formed when two solutions are mixed together.
(c) An acidic solution in which there is only partial ionization of the solute molecules.
Ans.: - (a) Alkali (b) Precipitate (c) Weak acid.
Q.18. Differentiate between the chemical nature of an aqueous solution of Hydrogen chloride and
an aqueous solution of Ammonia.
Ans.:Aqueous solution of
Hydrogen chloride
Aqueous solution of
Ammonia
It is acidic in nature
It is basic in nature
It turns blue litmus to red
It turns red litmus to
blue
It gives Hydronium ions in It gives hydroxyl ions in
the solution
the solution
Q.19. Write the balanced equations for the following reactions:
(a) Dilute Nitric acid producing Carbon dioxide.
(b) Dilute Sulphuric acid producing Hydrogen.
(c) Between Lead nitrate solution and dilute Sulphuric acid.
Ans : - (a) CaCO3 + 2HNO3 (dil) → Ca(NO3)2 + H2O + CO2
Na2CO3+ 2HNO3(dil) → 2NaNO3 + H2O + CO2
(b) Mg + H2SO4 (dil) → MgSO4 + H2
Zn + H2SO4 (dil) → ZnSO4 + H2
(c) Pb(NO3)2 + H2SO4 → PbSO4 ↓ + 2HNO3
Q.20. Choosing substances from the list given below, write equations for the reactions which you
would use in the laboratory to obtain in the box given below the list:
(i) Sodium sulphate (ii) Copper sulphate (iii) Iron (II) sulphate (iv) Zinc carbonate.
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Dilute
sulphuric acid
Copper Copper
sulphate
Iron
Sodium
carbonate
Sodium
Zinc
Ans : - (i) Na2CO3+ H2SO4 (dil) → Na2SO4 + H2O + CO2
(ii) CuCO3 + H2SO4 (dil) → CuSO4 + H2O + CO2
(iii) Fe + H2SO2 (dil) → FeSO4 + H2
(iv) Zn + H2SO4 (dil) → ZnSO4 + H2
ZnSO4+ Na2CO3→ ZnCO2 + Na2SO4
Q.21. From the formulae listed below, choose one, in each case, corresponding to the salt having
the given description :
AgCl, CuCO3, CuSO4.5H2O, KNO3, NaCl, NaHSO4, Pb(NO3)2, ZnCO3, ZnSO4.7H2O.
(i) An acid salt.
(ii) An insoluble Chloride.
(iii) On treating with concentrated Sulphuric acid, this salt changes from blue to white.
(iv) On heating, this salt changes from green to black.
(v) This salt gives Nitrogen dioxide on heating.
Ans : - (i) NaHSO4 (ii) AgCl (iii) CuSO4.5H2O (iv) CuCO3 (v) Pb(NO3)2
Q.22. The following table shows the tests a student performed on two aqueous solutions A, B.
Write down on your answer script the observation (i) and (ii) that were made.
Test
Observation Conclusion
(i) To solution A,
Barium chloride
solution and dilute
Hydrochloric acid were
added.
(i)
A contains
SO4-2 ions
(ii) To solution B,Silver
nitrate solution and
dilute Nitric acid were
added.
(ii)
B contains
Cl- ions
Ans : - (i) A white precipitate is formed which is insoluble in all mineral acids.
(ii) A white precipitate is formed which is soluble in excess of Ammonium hydroxide.
Q.23. The salt which in solution gives a pale green precipitate with NaOH solution and a white
precipitate with BaCl2solution :
(a) Iron [III] sulphate (b) Iron [II] sulphate (c) Iron [II] chloride (d) Iron [III] chloride.
Ans : - (b) Iron (II) sulphate.
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