The concentration of an acid/base/alkali is based on the number of moles of acid/bases dissolved in a decimeter (litre)of the solution.

 An acid/base/alkali with more acid/base/alkali in a decimeter(litre)  of solution is said to be concentrated while that with less is said to be dilute.(a) (i)strong acids have pH 1/2/3 while weak acids have high pH 4/5/6.

          (ii)a neutral solution have pH 7

           (iii)strong alkalis/bases have pH 12/13/14 while         weak bases/alkalis have pH 11/10 /9 / 8.

(b) pH is a measure of H+(aq) concentration in a solution.

The higher the H+(aq)ions concentration ;

  -the higher the acidity

  -the lower the pH

  -the lower the concentration of OH-(aq)

  -the lower the alkalinity

At pH 7 , a solution has equal concentration of H+(aq) and  OH-(aq).

Beyond pH 7,the concentration of the OH-(aq) increases as the H+(aq) ions decreases. 

(a) When acids /bases dissolve in water, the ions present in the solution conduct electricity.

 The more the dissociation the higher the yield of ions and the greater the electrical conductivity of the solution.

A compound that conducts electricity in an electrolyte and thus a compound showing high electrical conductivity is a strong electrolyte while a compound showing low electrical conductivity is a weak electrolyte.

(b) Practically, a bright light on a bulb ,a high voltage reading from a voltmeter high ammeter reading from an ammeter, a big deflection on a galvanometer is an indicator of strong electrolyte(acid/base) and the opposite for weak electrolytes(acids/base)

11. Some compounds exhibit/show both properties of acids and bases/alkalis.

A substance that react with both acids and bases is said to be amphoteric.

when reacting with nitric(V)acid, the oxide shows basic properties by reacting with an acid to form a simple salt and water only.

ZnO(s)    +    2HNO₃ (aq)    ->    Zn(NO₃ )₂ (aq)    +    H₂ O(l)

When Zinc oxide is reacted with sodium hydroxide the complex salt is sodium tetrahydroxozincate(II) complex salt.

ZnO(s)   + 2NaOH(aq) +    H₂ O(l)   -> Na₂ Zn(OH)₄ (aq)

Zn(OH)₂ (s) + 2HNO₃ (aq) -> Zn(NO₃)₂ (aq)+    2H₂ O(l)

When Zinc hydroxide is reacted with sodium hydroxide the complex salt is sodium tetrahydroxozincate(II) complex salt.

  Zn(OH) 2 (s)    +    2NaOH(aq)  ->   Na2Zn(OH) 4(aq)

 2.When Zinc hydroxide is reacted with potassium hydroxide the complex salt is potassium tetrahydroxozincate(II) complex salt.

when reacting with nitric(V)acid, the oxide shows basic properties by reacting with an acid to form a simple salt and water only. All other Lead salts are insoluble.

Chemical equation

 PbO(s)    +    2HNO3(aq)    ->   Pb(NO3) 2 (aq)   +    H2O(l)

When Lead(II) oxide is reacted with sodium hydroxide the complex salt is sodium tetrahydroxoplumbate(II) complex salt.

 PbO(s)    +    2NaOH(aq) +    H2O(l)   ->   Na2Pb(OH) 4(aq)

When Lead(II) oxide is reacted with potassium hydroxide the complex salt is potassium tetrahydroxoplumbate(II) complex salt.

when reacting with nitric(V)acid, the oxide shows basic properties by reacting with an acid to form a simple salt and water only.

Chemical equation

 Al2O3 (s)    +    6HNO3(aq) ->    Al(NO3)3 (aq)     +    3H2O(l)

When Aluminium(III) oxide is reacted with sodium hydroxide the complex salt is sodium tetrahydroxoaluminate(III) complex salt.

 Al2O3 (s)    + 2NaOH(aq) + 3H2O(l)   ->   2NaAl(OH) 4(aq)

2.When  Aluminium(III) oxide is reacted with potassium hydroxide the complex salt is potassium tetrahydroxoaluminate(II) complex salt.