practical 4 (Paper 1 +3) Topic Group 2+7 Inorganic Test Tube reactions

Question 1

Ba2+

Answer 1

Reagent used for Test ;H2SO4
Observation;White ppt.
Reason for Observation; Formation of BaSO4(s)
Equation; Ba2+(aq) + SO42−(aq) –> BaSO4(s)

Question 2

SO42−

Answer 2

Reagent used for Test ;BaCl2
Observation;White ppt.
Reason for Observation; Formation of BaSO4(s)
Equation;Ba2+(aq) + SO42−(aq)—> BaSO4(s)

Question 3

Mg2+

Answer 3

Reagent used for Test ;NaOH
Observation; White ppt.
Reason for Observation; Formation of Mg(OH)2(s)
equation;Mg2+(aq) + 2OH−(aq) –>
Mg(OH)2(s)

Question 4

OH-

Answer 4

Reagent used for Test ;MgCl2
Observation;White ppt.
Reason for Observation; Formation of Mg(OH)2(s)
Equation;Mg2+(aq) + 2OH−(aq) –>
Mg(OH)2(s)

Question 5

Cl−

Answer 5

Reagent used for Test ;AgNO3
Observation;White ppt.
Reason for Observation; Formation of AgCl(s)
Equation;Ag+(aq) + Cl−(aq) –>AgCl(s)

Question 6

Br−

Answer 6

Reagent used for Test ;AgNO3
Observation;Cream ppt.
Reason for Observation; Formation of AgBr(s)
Equation;Ag+(aq) + Br−(aq) à AgBr(s)

Question 7

AgCl

Answer 7

Reagent used for Test ;Dilute
NH3
Observation;AgCl ppt. dissolves
equation:AgCl(s) + 2NH3(aq)- ->[Ag(NH3)2]+(aq) + Cl−(aq)

Question 8

AgBr

Answer 8

Reagent used for Test ;Conc. NH3
Observation;AgBr ppt. dissolves
Reason for Observation;
Equation;AgBr(s) + 2NH3(aq)–> [Ag(NH3)2]+(aq) + Br−(aq)

Question 9

NH4+

Answer 9

Reagent used for Test ;NaOH & heat
Observation; Gas released turns red litmus paper blue
Reason for Observation; formation of NH3(g)
Equation;NH4+ + OH- –> NH3 + H2O

Question 10

CO32−
give 2 possible reagents

Answer 10

Reagent used for Test ;Any acid (HNO3 is best)
Observation; effervescence
Reason for Observation; Formation of CO2(g
2 HNO3 + Na2CO3 2NaNO3 + H2O + CO2
2HCl + Na2CO3  2NaCl + H2O + CO2

Question 11

I-

Answer 11

Reagent used for Test ;AgNO3
Observation;Yellow ppt.
Reason for Observation; Formation of AgI(s)
Equation;Ag+(aq) + I−(aq) –> AgI(s)

Question 12

why do we add nitric acid before adding silver nitrate to halide ion to distinguish between them give equation and reason

Answer 12

The role of nitric acid is to react with any carbonates present to prevent formation of the precipitate Ag2CO3 (white ppt). This would mask the desired observation
2 HNO3 + Na2CO3 2NaNO3 + H2O + CO2

Question 13

how do we remove insoluble salt

Answer 13

When making an insoluble salt, normally the salt would be removed by filtration, washed with distilled
water to remove soluble impurities and then dried on filter paper

Question 14

(TOPIC)
how to do test for sulphate
equation and observation and steps

Answer 14

1add hydrochloricacid to removed nay carbonate
2HCl + Na2CO3 –>2NaCl + H2O + CO2
(Fizzing due to CO2would be observed if a carbonate was present)
2.add barium chloride
Ba2+(aq) + SO42-(aq)–>BaSO4(s).(white ppt)

Question 15

(TOPiC)
what is Mg(OH)2 used in
give equation

Answer 15

Magnesium hydroxide is used in medicine (in suspension as milk of magnesia) to neutralise excess acid in the
stomach and to treat constipation.
Mg(OH)2+ 2HCl–>MgCl2+ 2H2O

Question 16

(TOPIC)
what is CaOH used in
equation

Answer 16

It is used in agriculture to neutralise
acidic soils.
An aqueous solution of calcium hydroxide is
called lime water and can be used a test for
carbon dioxide. The limewater turns cloudy
as white calcium carbonate is produced.
Ca(OH)2 (aq)+ CO2 (g)–>CaCO3 (s)+ H2O(l

Question 17

(TOPIC)
what kind of pH would Ba(OH)2 give when dissolved in water
equation and why

Answer 17

ph12-14
Barium hydroxidewould easilydissolve
in water. The hydroxide ions present
would make the solution strongly alkaline.
Ba(OH)2(S)+ aqBa2+(aq) + 2OH-(aq
)