Class 10
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Chemistry
Acids, Bases and Salts
NCERT Solutions
NCERT Solutions
Acids, Bases and Salts
34 Solutions
Exercise:
All Exercises
Exercises
In-text Questions Page 18
In-text Questions Page 22
In-text Questions Page 25
In-text Questions Page 28
In-text Questions Page 33
Q1
Exercises
A solution turns red litmus blue, its pH is likely to be
(a)
1
(b)
4
(c)
5
(d)
10
Q2
Exercises
A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains
(a)
NaCl
(b)
HCl
(c)
LiCl
(d)
KCl
Q3
Exercises
10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount HCl solution (the same solution as before) required to neutralise it will be
(a)
4 mL
(b)
8 mL
(c)
12 mL
(d)
16 mL
Q4
Exercises
Which one of the following types of medicines is used for treating indigestion?
(a)
Antibiotic
(b)
Analgesic
(c)
Antacid
(d)
Antiseptic
Q5
Exercises
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.
Q6
Exercises
Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an Activity to prove it.
Q7
Exercises
Why does distilled water not conduct electricity, whereas rain water does?
Q8
Exercises
Why do acids not show acidic behaviour in the absence of water?
Q9
Exercises
Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1, 11, 7 and 9, respectively. Which solution is
(a)
neutral?
(b)
strongly alkaline?
(c)
strongly acidic?
(d)
weakly acidic?
(e) weakly alkaline?
Arrange the pH in increasing order of hydrogen-ion concentration.
Q10
Exercises
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 (
C
H
3
C
O
O
H
CH_3COOH
C
H
3
COO
H
) is added to test tube B. Amount and concentration taken for both the acids are same. In which test tube will the fizzing occur more vigorously and why?
Q11
Exercises
Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.
Q12
Exercises
A milkman adds a very small amount of baking soda to fresh milk.
(a)
Why does he shift the pH of the fresh milk from 6 to slightly alkaline?
(b)
Why does this milk take a long time to set as curd?
Q13
Exercises
Plaster of Paris should be stored in a moisture-proof container. Explain why?
Q14
Exercises
What is a neutralisation reaction? Give two examples.
Q15
Exercises
Give two important uses of washing soda and baking soda.
Q1
In-text Questions Page 18
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?
Q1
In-text Questions Page 22
Why should curd and sour substances not be kept in brass and copper vessels?
Q2
In-text Questions Page 22
Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?
Q3
In-text Questions Page 22
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.
Q1
In-text Questions Page 25
Why do HCl,
H
N
O
3
HNO_3
H
N
O
3
, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Q2
In-text Questions Page 25
Why does an aqueous solution of an acid conduct electricity?
Q3
In-text Questions Page 25
Why does dry HCl gas not change the colour of the dry litmus paper?
Q4
In-text Questions Page 25
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Q5
In-text Questions Page 25
How is the concentration of hydronium ions (
H
3
O
+
H_3O^+
H
3
O
+
) affected when a solution of an acid is diluted?
Q6
In-text Questions Page 25
How is the concentration of hydroxide ions (
O
H
−
OH^-
O
H
−
) affected when excess base is dissolved in a solution of sodium hydroxide?
Q1
In-text Questions Page 28
You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?
Q2
In-text Questions Page 28
What effect does the concentration of
H
+
(
a
q
)
H^+(aq)
H
+
(
a
q
)
ions have on the nature of the solution?
Q3
In-text Questions Page 28
Do basic solutions also have
H
+
(
a
q
)
H^+(aq)
H
+
(
a
q
)
ions? If yes, then why are these basic?
Q4
In-text Questions Page 28
Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?
Q1
In-text Questions Page 33
What is the common name of the compound
C
a
O
C
l
2
CaOCl_2
C
a
OC
l
2
?
Q2
In-text Questions Page 33
Name the substance which on treatment with chlorine yields bleaching powder.
Q3
In-text Questions Page 33
Name the sodium compound which is used for softening hard water.
Q4
In-text Questions Page 33
What will happen if a solution of sodium hydrogencarbonate is heated? Give the equation of the reaction involved.
Q5
In-text Questions Page 33
Write an equation to show the reaction between Plaster of Paris and water.
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