ACID, BASE
AND SALTS
Time:
2 hrs M.M 40
General
Instructions
- All questions are compulsory.
- Write chemical equations wherever required.
- Draw neat and clean diagrams.
- Question no. 01 to 10 carries 01 marks each.
- Question no. 11 to 14 carries 02 marks each.
Que. 1 Why
does distilled water not conducts electricity, whereas rainwater does?
Que. 2
Fresh milk has a pH 6. How do you think the pH will change as it becomes sour?
Que. 3
What is alkalis?
Que. 4 How
is concentration of hydroxide ions (OH-) affected when excess of
base is dissolved in a solution of sodium hydroxide?
Que. 5 What is acid rain? How does it affect our
aquatic life?
Que. 6 What happens during a bee sting?
What is its remedy?
Que. 7 Two
solutions X and Y are tested with universal indicator. Solution X turns orange
whereas solution Y turns red. Which of the solution is a stronger acid?
Que.
8 Why does dry HCI gas not change the colour of the dry litmus paper?
Que. 9 Three
solutions A, B and C have pH, values of 6, 4 and 10 respectively. Which of the
solution is highly acidic?
Que. 10 Why should curd and sour substances
not be kept in brass and copper vessels?
Que. 11 State Arrhenius Concept of acids and
bases. Giving reason, select a strong acid and a weak base from amongst the
following substances:
H2CO3, HNO3,
NaOH, NH4OH
Que. 12 Sate the chemical property in each case on
which the following uses of baking soda are based.
(i)
as an antacid.
(ii) as a constituent of baking
powder
Que. 13 What happens when
(i)
plaster of Paris is heated to 473 K? (ii) plaster of Paris is mixed with water?
Que. 14 What happens
when
(a)
solid sodium hydrogen carbonate is heated,
(b)
chlorine gas is passed through dry slaked lime,
Que. 15 (i) Why are acids not stored in meal
containers? Containers made from which material are safe to store acids.
(ii)
Explain why does dry hydrochloric acid not conduct electricity but its aqueous
solution
conducts electricity.
(iii) Why are commercial samples of
bleaching powder not completely soluble in water?
Que. 16 A metal compound ‘X’ reacts with
dilute hydrochloric acid to produce gas (Y). The gas (Y) evolved extinguishes a
burning candle. Write a balanced chemical equation for the reaction if one of
the compounds formed is calcium chloride. Write names of X & Y.
Que. 17 Explain the pH change as the
cause of tooth decay. How can tooth decay caused by pH change be prevented?
Que.
18 Equal lengths of magnesium ribbons are taken in test tubes A and B.
Hydrochloric acid (HCI) is added to test tube A, while acetic acid (CH3 COOH)
is added to test tube B. In which test tube will the fizzing occur more
vigorously and why?
Que.
19 Write one activity to show the reaction of acids with metal
Carbonates/Bicarbonates salts.
Or
Compounds
like alcohol and glucose also contain hydrogen but are not categorized as
acids. Describe an activity to prove it.
Que.
20 Identify the compounds of calcium which is yellowish white powder and
is used for disinfecting drinking water. How is it manufactured? White the
chemical equation for the reaction involved. What happens when it is left
exposed to air?
Or
What
happens when
(i)
Aluminium metal reacts with dilute HCI?
(ii)
Potassium oxide is dissolved in water?
(iii)
Sodium hydroxide reacts with sulphuric acid completely?
Give equation for the chemical
reactions involved.
Prepared
by:
Sinha
Sir
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