Class X Holiday Homework - CHEMISTRY
1. With the help of chemical equations, show that water acts both as an
acid and a base.
2. Between dilute and concentrated samples of sulphuric acid which sample
will have a higher H+ ion concentration? Which sample will have lower pH
value?
3. Salts of which base do not contain metal ion? Support your answer citing
a reaction.
4. How is neutralization of carbonate different from the neutralization of
an oxide or a hydroxide?
5. Metal compound A reacts with dilute HCl to produce effervescence. The
gas evolved extinguishes a burning candle. Write the balanced chemical
equation for the reaction when one of the compounds formed is calcium
chloride.
6. Dry hydrogen chloride gas does not turn blue litmus red whereas
hydrochloric acid does. Give reasons.
7. Which gas is generally liberated when an acid reacts with a metal?
Illustrate with an example. How will you test the presence of this gas?
8. What does pH stand for? What does a pH scale indicate? A student
drooped few pieces of marble in dilute HCl contained in a test tube. The
evolved gas was passed through lime water. What change would be
observed in lime water? Write balanced chemical equation for the
reaction when (i) gas was evolved (ii) gas was passed through lime water.
9. Starting from sodium hydroxide, how will you prepare crystals of
a. Sodium nitrate
b. Sodium sulphate
10. Name the products obtained on electrolysis of aqueous solution of sodium
chloride. Why this process is called chlor-alkali process?
11. What is baking soda? How does it make cake smooth and spongy? What is
meant by water of crystallization? How will you show that blue copper
sulphate crystals contain water of crystallization?
12. Name the two main chemicals used for making a soda- acid fire
extinguisher. How does the soda-acid fire extinguisher help to put off
the fire?
13. What is the chemical name of washing soda? Name the three chief raw
materials used for making washing soda?
14. You have been provided with three test tubes. One of them contains
distilled water and the other two contain an acidic solution and a basic
solution, respectively. If you are given only red litmus paper, how will you
identify the contents of each test tube?
15. Why should curd and sour substances not be kept in brass and copper
vessels?
16. Why do HCl, HNO 3, etc., show acidic characters in aqueous solutions
while solutions of compounds like alcohol and glucose do not show acidic
character?
17. While diluting an acid, why is it recommended that the acid should be
added to water and not water to the acid?
18. What will happen if a solution of sodium hydrogen carbonate is heated?
Give the equation of the reaction involved.
19. A drop of litmus solution is added to each of the four solutions given
below. State the colour of litmus solution observed in each: Soap solution,
Sodium bicarbonate solution, Acetic acid, Tomato juice
20. A compound which is prepared from gypsum has the property of
hardening when mixed with a proper quantity of water. Identify the
compound. Write the chemical equation for its preparation. For what
purpose is it used in hospital?
21. Write word equations and then balanced equations for the reaction taking
place when –(a) dilute sulphuric acid reacts with zinc granules (b) dilute
hydrochloric acid reacts with magnesium ribbon.(c) dilute sulphuric acid
reacts with aluminium powder.(d) dilute hydrochloric acid reacts with iron
filings.
22 . (a) Why does an aqueous solution of acid conduct electricity?
(b) Why should plaster of Paris be stored in a moisture proof container?
(c) Why is baking soda used as an antacid?
23 . A white coloured powder is used by the doctors for supporting
fractured bones.
(a) Write chemical name of the powder.
(b) Write its formula.
(c) Write chemical equation, when this white powder is mixed with water.