Acids, Bases and Salts
Multiple Choice Questions (MCQs)
with a solution of a
Q. 1What happens when a solution of an acid is mixed
base in a test tube?
() The temperature of the solution increases.
(i) The temperature of the solution decreases.
(ii) The temperature of the solution remains the same.
(iv) Salt formation takes place.
(a) Only ) b) () and (u
Thinking Process
salt and water
(u) In eNOthermc process heat rs cov
reacton takes piace to torm sat and
Ans. (d) When an ackd reacts with a base neutratsaton ot he soutn inceases
water and t s an exothermcreacton So the terrper ature
Excess addition of
Q. 2 An aqueous solution turns red litmus solution blue.
which of the following solution would reverse the change?
(a) Baking powder b iime
() Ammonium hydroxide solution ftydrox hlonc acid
soluton blue So ts a tbasic compound
Ans. (d) Since, the aqueOus soluton turns red ltius HCI woud turn bJe itmus
An acid solution (HC) wOuid reverse the change That s
solution to red.
sokuton are basic
Other options baking powoer ime and amYonaum ydroxde these
compounds So. the blue tmus soution woud not change the coiour by adding
Compounds
humidday. the gas
Q. 3 Duing the preparation of hydrogen chloride gas on acalcium
is usuallypassed through the guard tube containing chloride. The
to
role of calcium chloride taken in the guard tube is
(a) absorb the evolved gas (b moisten the gas
)absorb moisture from the gas d) absorb Ci ions from the evolved gas
, Soutions
18 NCERT Exemplar (Class
osture ror e s ecase
chlorkdes (C))s to absorb
AUS. (C) The roBe of calcium
cakcium chioride is aoOd dehydrating agent
crystallisation?
water of
Q.4 Which of the following salts does not contain
)Washing oda
(a) Blue vitriol ( 8aking soda
"Thinking Process
hytrated salts
carbonate Chermca
soda s NaHCO, (sOdium hydrogen
Ans. (b) Checal formula ot bgk1ng washing sota s Na .CO, 10.O ad
gYosum
formulae of blue vitriol is CuSO, 5H.O
Is CaSO, 2H,0
of crystaisaton
So, baking powder does not contan water
Q.5Sodium carbonate is a basic salt because it is a salt
of
and weak base
(b) weak dcid
(a) strong acid and strong base
Mweak dcid and strong base
() strong acid and weak base
Thinking Process ts
gve busc soutios (
The salts of weck acids and strong buses
having pH more than 7.
salt of weak acid cartonic acid (H.CO,) and
a
Ans. (d) Sodium carbonate ( Na .C0,) is the
strong base sodiumhydroxide (NaOH).
2NaOH + H,CO, Na C0, +2H.0
Sotum Catonic Water
hycorovde C
Its nature is
Q. 6Calcium phosphate is present in tooth(c)enamel.
neutral d) amphoteric
Aa) basic (b) acidic
Thinking Process
3Ca(OH), +2H,PO,Ca(PO), + H,0
Calcum PhosphoK Caum
hydrovde phughae
a salt of weak acid (phosphonc
Ans. (a) Calcium phosphate Ca(PO,), is basic salt. as it is (though both are weak). Also
acid) and slightly stronger base (calcium hydroxide)
mouth is acioic.
when pH of our mouth falls below 5.5 due to eating of sweets etc.., ie.,
calcium
the dissolution of enamel (calcium phOsphate) starts which shows that
phosphate is basic in nature.
0. 7A sample of soil is mixed with water and allowed to settle. The clear
supernatant solution turns the pH paper yellowish-orange. Which of the
following would change the colour of this pH paper to greenish-blue?
(a) Lemon juice (b) Vinegar (c)Comnmon salt t An antacid
Ans. (d) As pH paper turns greenish blue tor weakly basic compound and antacids contain
weak base like Mg(OH), So, anantacid would change the cotour of this pH paver to
oreenish-blue Other options (a) and (b)contain acids and option (c) is a neutral sat
Multiple Choice Questions (MCQs)
with a solution of a
Q. 1What happens when a solution of an acid is mixed
base in a test tube?
() The temperature of the solution increases.
(i) The temperature of the solution decreases.
(ii) The temperature of the solution remains the same.
(iv) Salt formation takes place.
(a) Only ) b) () and (u
Thinking Process
salt and water
(u) In eNOthermc process heat rs cov
reacton takes piace to torm sat and
Ans. (d) When an ackd reacts with a base neutratsaton ot he soutn inceases
water and t s an exothermcreacton So the terrper ature
Excess addition of
Q. 2 An aqueous solution turns red litmus solution blue.
which of the following solution would reverse the change?
(a) Baking powder b iime
() Ammonium hydroxide solution ftydrox hlonc acid
soluton blue So ts a tbasic compound
Ans. (d) Since, the aqueOus soluton turns red ltius HCI woud turn bJe itmus
An acid solution (HC) wOuid reverse the change That s
solution to red.
sokuton are basic
Other options baking powoer ime and amYonaum ydroxde these
compounds So. the blue tmus soution woud not change the coiour by adding
Compounds
humidday. the gas
Q. 3 Duing the preparation of hydrogen chloride gas on acalcium
is usuallypassed through the guard tube containing chloride. The
to
role of calcium chloride taken in the guard tube is
(a) absorb the evolved gas (b moisten the gas
)absorb moisture from the gas d) absorb Ci ions from the evolved gas
, Soutions
18 NCERT Exemplar (Class
osture ror e s ecase
chlorkdes (C))s to absorb
AUS. (C) The roBe of calcium
cakcium chioride is aoOd dehydrating agent
crystallisation?
water of
Q.4 Which of the following salts does not contain
)Washing oda
(a) Blue vitriol ( 8aking soda
"Thinking Process
hytrated salts
carbonate Chermca
soda s NaHCO, (sOdium hydrogen
Ans. (b) Checal formula ot bgk1ng washing sota s Na .CO, 10.O ad
gYosum
formulae of blue vitriol is CuSO, 5H.O
Is CaSO, 2H,0
of crystaisaton
So, baking powder does not contan water
Q.5Sodium carbonate is a basic salt because it is a salt
of
and weak base
(b) weak dcid
(a) strong acid and strong base
Mweak dcid and strong base
() strong acid and weak base
Thinking Process ts
gve busc soutios (
The salts of weck acids and strong buses
having pH more than 7.
salt of weak acid cartonic acid (H.CO,) and
a
Ans. (d) Sodium carbonate ( Na .C0,) is the
strong base sodiumhydroxide (NaOH).
2NaOH + H,CO, Na C0, +2H.0
Sotum Catonic Water
hycorovde C
Its nature is
Q. 6Calcium phosphate is present in tooth(c)enamel.
neutral d) amphoteric
Aa) basic (b) acidic
Thinking Process
3Ca(OH), +2H,PO,Ca(PO), + H,0
Calcum PhosphoK Caum
hydrovde phughae
a salt of weak acid (phosphonc
Ans. (a) Calcium phosphate Ca(PO,), is basic salt. as it is (though both are weak). Also
acid) and slightly stronger base (calcium hydroxide)
mouth is acioic.
when pH of our mouth falls below 5.5 due to eating of sweets etc.., ie.,
calcium
the dissolution of enamel (calcium phOsphate) starts which shows that
phosphate is basic in nature.
0. 7A sample of soil is mixed with water and allowed to settle. The clear
supernatant solution turns the pH paper yellowish-orange. Which of the
following would change the colour of this pH paper to greenish-blue?
(a) Lemon juice (b) Vinegar (c)Comnmon salt t An antacid
Ans. (d) As pH paper turns greenish blue tor weakly basic compound and antacids contain
weak base like Mg(OH), So, anantacid would change the cotour of this pH paver to
oreenish-blue Other options (a) and (b)contain acids and option (c) is a neutral sat
