Grade: 10
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Acids, Bases and Salts- REVISION
(a) Write the name given to bases that are highly soluble in water? Give an example. (b) How is tooth decay related to pH? How can
it be prevented? (c) Why does bee sting cause pain and irritation? Rubbing of baking soda on the sting area gives relief. How?
Differentiate between strong and weak acids. Identify the strong and weak acids from the following list of acids. Hydrochloric acid,
acetic acid, formic acid, nitric acid.
(i) Name the gas which is liberated when an acid reacts with a metal? How will you test the presence of this gas? (ii) Write the
chemical equation for the reaction of zinc metal With (a) hydrochloric acid and (b) with sodium hydroxide. Write the chemical name
of salt obtained in each case. (iii) Identify the acid and base for ammonium chloride salt. What would be the nature of this salt?
Mention the pH range of this salt.
(i) Explain why is hydrochloric acid a strong acid and acetic acid, a weak acid ? How can it be verified? (ii) Explain why aqueous
solution of an acid conducts electricity. (iii) You have four solutions A, B, C and D. The pH of solution A is 6, B is 9, C is 12 and D is 7,
(a) Identify the most acidic and most basic solutions. (b) Arrange the above four solutions in the increasing order of H + ion
concentration. (c) State the change in colour of pH paper on dipping in solution C and D.
A student dropped few pieces of marble in dilute hydrochloric acid, contained in a test tube. The evolved gas was then passed through
lime water. What change would be observed in lime water? What will happen if excess of gas is passed through lime water? With the
help of balanced chemical equations for all the changes explain the observations.
(a) Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9 respectively. Which solutions is
:
(i) neutral (ii) strongly alkaline (iii) strongly acidic (iv) weakly acidic and (v) Weakly alkaline Arrange the solutions in increasing
order of H-ion concentration.
(a) You are given two solutions A and B. The pH of solution A is 6 and pH of solution B is 8. (i) Identify the acidic and basic solution
(ii) Which solution has more H+ ion concentration? Give reason for your answer. (b) Why is HCl a stronger acid than acetic acid?
Explain.
(a) Tooth decay starts when the pH of the mouth is lower than 5.5. Explain how the tooth paste prevents tooth decay. (b) Name the
acids present in: (i) Nettle sting (ii) Curd. (c) State the soil conditions under which a farmer treats the soil of his field with quick lime
or slaked lime.
(a) You have three solutions - A, B, and C having a pH of 6, 2 and 9 respectively. Arrange these solutions in increasing order of
hydrogen ion concentration. Which of the three is most acidic? What happens to the hydrogen ion concentration in A as it is diluted?
(b) If someone is suffering from a stomach problem called acidity, why is a solution of baking soda offered as a remedy?
To a solution of sodium hydroxide in a test tube two drops of phenolphthalein are added. (i) State the colour change observed.
(ii) If dil HCl is added drop wise to the solution, what will be the colour change? (iii) On adding few drops of NaOH solution to the
above mixture the colour of the solution reappears. Why?
It has been observed that dry hydrogen chloride gas does not turn blue litmus red whereas hydrochloric acid does. Explain this
observation with the help of an activity and state the reason behind it.
(a) Bee sting leaves a chemical substance that causes pain and irritation. Name the chemical substance. Identify the type of substance
which may give relief on the stung area when applied on it. (b) Mention the pH value below which tooth decay begins. How this fall
below this value? Explain the ill effect of the acidic medium in the mouth. How can this be prevented? (c) What are strong acids and
weak acids? Give an example of each.
(a) State the chemical name and formula of bleaching powder. Write the chemical equation for its preparation. Also mention its two
uses other than bleaching. (b) There are three test tubes A, B, C. Test tube ‘A’ has an acidic solution, test tube ‘B’ has a basic solution
and test tube ‘C’ has distilled water. Identify the contents of each test tube with the help of litmus paper.
(a) A metal compound ‘X’ reacts with dil. H2SO4 to produce effervescence. The gas evolved extinguishes a burning candle. If one of the
compound formed is calcium sulphate, then what is ‘X’ and the gas evolved? Also write a balanced chemical equation for the reaction
which occurred. (b) (i) Name one antacid. How does it help to relieve indigestion in stomach? (ii) A farmer treats the soil with quick
lime or calcium carbonate. What is the nature of soil? Why does the farmer treat the soil with quick lime?
Write the names of the products formed when zinc reacts with NaOH. Also write the balanced chemical equation for the reaction
involved. Write a test to confirm the presence of the gas evolved during this reaction.
(a) State one example of a synthetic indicator and an olfactory indicator? (b) How do bacteria decay our teeth? Why do we basic tooth
pastes for cleaning our teeth?
(a) You have two solutions X and Y. the pH of solutions X is 5 and pH of solution Y is 8. Which solution has more hydrogen ion
concentration? Which of this is acidic and which one is basis? (b) While diluting an acid, why is it recommended that the acid should
be added to water and not water to the acid? (c) Write the balanced chemical equation for the action of granulated zinc with sodium
hydroxide. Name the products formed.
(a) Write the chemical reaction of metal carbonates with acid. What happens on passing this gas evolved above, over lime water?
Write the chemical equation for it. (b) Give the reaction involved in the manufacture of caustic soda by chlor – alkali process. How can
this reaction be used simultaneously for the manufacture of HCl acid? Why is it called chlor-alkali process?
Give reasons: (i) Copper vessels develop a green coating when exposed in air. (ii) Acids like HCl and HNO3 show acidic characters in
aqueous solutions while solutions of compound like alcohol and glucose do not show acidic character. (iii) Dry HCl gas does not
change the colour of the dry litmus paper.
Mr. P.H.Ganeshan, Chemistry Teacher
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(a) What is a neutralization reaction? Give two examples.
(b) Metal compound ‘A’ reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle.
Write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.
A metal is treated with dilute sulphuric acid. The gas evolved is collected by a method as shown in the figure.
Answer the following questions: (a) Name the gas. (b) Is the gas soluble or insoluble in water? (c) Is the gas lighter or heavier than
air? Justify your answer with reason in each case.
(a) Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A while acetic
acid (CH3COOH) is added to test tube B. In which test tube will fizzing occur vigorously and why? Write equation to show the gas
evolved.
(b) Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Justify your answer. Why a milkman does
adds a small amount of baking soda to fresh milk?
Demonstrate by an experiment that acid reacts with metal carbonate to liberate carbon dioxide gas.
(a) What are olfactory indicators? Give an example. (b) Name two naturally occurring acids and mention their source.
(c) Zinc reacts with HCl and NaOH both to produce H2 gas. Write balanced equation for both reactions.
Give reasons: (a) Acid must be added to water and not vice versa during dilution. (b) Solution of sulphuric acid conducts electricity
whereas alcohol does not. (c) Dry ammonia gas has no action on litmus paper but a solution of ammonia in water turns red litmus
paper blue.
In an activity to investigate whether all compounds containing hydrogen are acidic.
(a) Draw a well labelled experimental set – up for the activity. (b) State what is observed giving reasons for the following when.
(i) Current is passed through dilute hydrochloric acid in the beaker. (ii) Current is passed through glucose and alcohol solutions in the
beaker.
(a) With the help of a labelled diagram demonstrate an experiment to show the reaction between sodium carbonate and dilute
hydrochloric acid. (b) Name the gas evolved. (c) Suggest the test for the gas evolved. (d) Write equation for the chemical reactions
involved.
A solution of a substance ‘X' is used for testing carbon dioxide. Identify ‘X'. What will be its reaction with carbon dioxide? Write
balanced equation for the reaction?
(a) What are antacids? State their role in the treatment of indigestion. (b) What happens when an acid is added to water? Explain
with the help of equation. Give two examples of naturally occurring acid and also mention its source.
(i) Write balanced chemical equations only for the following chemical properties of acids: (a) when an acid reacts with a metal.
(b) when an acid reacts with a metal bicarbonate. (c) when an acid reacts with a base. (ii) Three solutions A, B and C have pH values 5,
8 and 10 respectively. Amongst the three which solution has maximum hydrogen ion concentration? Classify the nature of the three
solutions as acidic or basic.
Naman and Raghav perform an experiment in which they mix concentrated sulphuric acid with water. Naman mixes water to acid
and Raghav mixes acid to water slowly with constant stirring. Mention the suitable reason for selecting the one which you find is a
correct method and discarding the one which is wrong.
Two test tubes A and B are taken containing solid sodium carbonate and sodium hydrogen carbonate respectively. Some dilute HCl is
poured in both the test tubes. (i) Name the main products formed with their chemical formula in A and B. (ii) State the similarity
between both the activities. (iii) Name the compound that is formed when electricity is passed through an aqueous solution of the
main product obtained in the above mentioned activity. (iv) State your observation with a balanced chemical equation when the gas
evolved in test tube B during the activity passes through lime water.
Mr. P.H.Ganeshan, Chemistry Teacher