basic chemistry knowledge on acid and bases

1. Revision acid and base

2. 1) Give formulae for these substances
A) hydrochloric acid HCl
B) sulphuric acid H SO4
2
C) nitric acid HNO3
D) ethanoic acid CH3COOH
E) Sodium hydroxide NaOH
F) Potassium hydroxide KOH
G) Barium hydroxide Ba(OH)2

3. 2) Give examples of
• A) strong acids HCl, H2SO4, HNO3
• B) Weak acids CH3COOH, ethanoic acid
• C) Strong alkali NaOH, KOH, Ba(OH)2
• C) Weak alkali NH4OH,

4. 3) State 4 chemical properties of acids
• A) reacts with metals to form
SALT + HYDROGEN GAS
• B) reacts with oxide metals to form
SALT + WATER
• C) reacts with alkali to form
SALT + WATER
• D) reacts with carbonate metals to form
SALT + CARBON DIOXIDE + WATER

6. Fill in the table below
Beaker A Beaker B
a) Add blue dry BLUE LITMUS PAPER NO
litmus paper CHANGE TO RED CHANGE
b) Add EFFERVESCENCE OCCUR.
magnesium COLOURLESS GAS RELEASE NO
ribbon WHICH GIVES ‘POP’ SOUND CHANGE
WHEN TESTED WITH BURNING
WOODEN SPLINTER
c) Add marble
EFFERVESCENCE OCCUR.
chips NO
COLOURLESS GAS
CHANGE
RELEASE WHICH TURN
LIME WATER CLOUDY

7. • Which beaker shows acidic property? Why?
Beaker A because hydrogen chloride
ionised in water to form H+ ions.
Therefore it shows the acidic properties
• What is the role of water in this experiment?
To ionise hydrogen chloride into H+ ions
and show its acidic properties

8. Write chemical equations for reactions
in beaker A)
• i) with magnesium ribbon
2 HCl + Mg → MgCl2 + H 2
• ii) with marble chips
2 HCl + CaCO3 → CaCl2 + CO2 + H 2O

9. Does solution formed in beaker A conduct
electricity? Explain your answer
Yes because solution A contain
mobile/free moving ion.

10. 5) Table below shows some solutions with different pH
substan Solution Solution Solution Solution Solution
ce A B C D E
pH 2 5 7 8 13
values

11. Which solution is
b)A strong acid? Solution A
c)A strong alkali? Solution E
d)Neutral solution? Solution C
e)Weak acid? Solution B
f)Weak alkali? Solution D
g)Has high concentration of hydrogen
ions? Solution A
h)Has low concentration of hydroxide
ions? Solution E

12. 6) Calculations on concentrations
• 4 grams of sodium hydroxide is dissolved in
100 cm3 of water
• Calculate concentration of the solution
formed in: A) g/dm3

13. 6) Calculate concentration of the
solution formed in
B) mol/dm3 1000 cm3 = 1 dm3

14. 8) Calculations on formula,
mole = MV/1000 and
mole = mass/molar mass
• How many moles of NaOH contained in 100 cm3
of 2.0 mol dm-3 NaOH solution ?

15. What is the mass of NaOH needed to make a
solution of 100 cm3 NaOH concentration 0.2
moldm-3? ( given RAM Na, 23: O,16: H,1)

16. What is the concentration of 0.5 moles HCl in a
volume of 100 cm3 solution ?

17. 7) Calculations on titration
• 100 cm3 of 0.2 mol /dm3 sulphuric acid
neutralise exactly 100 cm3 of sodium
hydroxide solution
Calculate the concentration of the sodium
hydroxide solution
[H+] Ma Va = [OH] Mb Vb
2x 0.2 x 100 = 1 x Mb x 100
So Mb = 2 x 0.2 x 100 /100
= 0.4 mol dm-3

18. 8) Calculations on dilution
• 90 cm3 of distilled water is added to a volume of
10 cm3 of nitric acid with a concentration of 2.0
mol /dm3. What is the concentration of acid after
the dilution?
M 1V1 = M 2V2
2(10) = M 2 (100)
−3
∴ M 2 = 0.2moldm